Flooring Glossary

Plain-language definitions of the terms you meet on a spec sheet, in a showroom, or in a quote — written by us, and sourced to the bodies that own them.

214 terms · Last verified 21 July 2026

A

AC rating Laminate: An abrasion-class scale for laminate, from AC1 to AC5 (and AC6), rating resistance to abrasion, impact, and wear. AC3 suits most homes; AC4 to AC5 targets light-commercial and commercial traffic. The AC scale comes from the European EN 13329 standard, while in North America NALFA certifies laminate to its own performance standard. Source: EN 13329 / NALFA
Acacia Acacia spp. Species: Also sold as: Asian walnutA widely sold exotic, roughly 1,700 to 2,300 Janka depending on type, known for dramatic colour variation and short board lengths. It is hard and affordable but visually busy.
Acclimation Installation: Letting flooring sit inside the room where it will be installed until it reaches that space's normal temperature and humidity. Because wood- and fibre-based floors expand and contract with moisture, skipping acclimation is a leading cause of gapping, cupping, and buckling later. Source: NWFA
Aluminum-oxide finish Finish: A factory-applied finish infused with aluminum oxide, a very hard mineral, giving prefinished wood and laminate strong scratch and wear resistance. It is tough but difficult to spot-repair on site.
Amendoim Pterogyne nitens Species: Also sold as: Brazilian oak, ironwood (not a true oak)A warm reddish-brown South American wood at about 1,900 Janka with an attractive wavy grain; sometimes marketed as Brazilian oak, though it is unrelated.
American Beech Fagus grandifolia Species: A pale, straight-grained hardwood at about 1,300 Janka with a fine, uniform texture. It is stable and hard but stocked as flooring less often than oak or maple.
American Cherry Prunus serotina Species: Also sold as: black cherryA warm, red-brown wood, soft at about 950 Janka, that famously darkens and deepens with exposure to light. Its beauty comes at the cost of easy denting.
ANSI Standards: The American National Standards Institute, which coordinates and accredits the voluntary consensus standards used across US flooring, such as the A108, A118, and A137 family for ceramic tile. ANSI does not sell floors; it stewards the standards others write. Source: ANSI
Appearance grade Wood: A classification of how much natural character, such as knots, colour variation, and mineral streaks, a batch of wood flooring shows. Higher clear grades look uniform and cost more; lower grades show more character but are structurally the same wood. Source: NHLA / NWFA-NOFMA
ASTM Standards: ASTM International, which publishes many of the test methods flooring relies on, including slab-moisture tests (F2170, F1869) and tile properties (C373). When a spec cites an F or C number, it is usually an ASTM method. Source: ASTM
Attached underlayment Installation: A foam or cork pad bonded to the underside of a plank at the factory, adding cushioning and sound damping without a separate underlayment step. It is convenient but does not remove the need to address subfloor moisture.
Australian Cypress Callitris glaucophylla Species: Also sold as: white cypress pineA knotty, honey-gold softwood at about 1,375 Janka, prized for its dramatic dark knots and rustic character rather than uniformity.

B

Backer board Tile: A rigid cement-based or fibre-cement panel installed as a stable, water-durable base for tile, especially over wood subfloors and in wet areas. It gives thinset a sound surface to grip and resists the movement and moisture that would crack tile set directly on plywood.
Backing layer Anatomy: The bottom layer of a plank or tile, which balances the board against warping and can add moisture resistance or sound damping.
Bamboo Phyllostachys edulis (moso) Materials: A floor made from a fast-growing grass rather than a hardwood, processed into solid, engineered, or strand-woven forms. Strand-woven bamboo is exceptionally hard, but bamboo's real-world durability and moisture behaviour depend heavily on manufacturing quality.
Bevel Anatomy: A small chamfer along a plank's edges that creates a subtle groove between installed boards. Bevels define each plank and help hide tiny height differences; a micro-bevel is a smaller version of the same idea.
Black Walnut Juglans nigra Species: Also sold as: American walnutA prized domestic hardwood with rich chocolate-brown colour and straight grain, but relatively soft at about 1,010 Janka, so it dents more easily than oak. It is chosen for its looks more than its toughness.
Blackbutt Eucalyptus pilularis Species: A pale golden Australian hardwood at about 2,100 Janka, prized for its subtle, even appearance and popular in new homes. It is also valued for its bushfire resistance.
Bleached / white-washed Finish: Techniques that lighten wood, either by chemically bleaching out its natural colour or by applying a thin white-tinted finish, to achieve pale, Scandinavian-style floors.
Board foot Measurement: A unit of lumber volume equal to a piece 12 inches by 12 inches by 1 inch thick. It is used for pricing solid wood, though finished flooring is usually sold by the square foot.
Bolivian Rosewood Machaerium spp. Species: Also sold as: pau ferro, Santos rosewood, morado (not a true rosewood)A dense, dark exotic sold as rosewood but botanically not a true rosewood, which belongs to the Dalbergia genus. It is prized for rich colour and hardness; here the trade name is about looks, not lineage.
Brazilian Cherry (Jatoba) Hymenaea courbaril Species: Also sold as: Jatoba (not a true cherry)A South American exotic and long-time flooring favourite, very hard at about 2,350 Janka, with a deep red-brown colour that darkens noticeably with light. It is not related to true cherry.
Brazilian Teak (Cumaru) Dipteryx odorata Species: Also sold as: Cumaru, southern chestnut (not a true teak)A very hard South American species at about 3,500 Janka, tan to reddish-brown with an interlocked, sometimes wavy grain. It is unrelated to true teak but shares a reputation for toughness.
Brazilian Walnut (Ipe) Handroanthus spp. Species: Also sold as: Ipe, lapacho, pau d'arco (not a true walnut)One of the hardest, densest woods on earth at roughly 3,680 Janka, olive-brown and naturally oily. Its extreme hardness makes it superb for durability and decking but demanding to cut and fasten.
Brushbox Lophostemon confertus Species: Also sold as: Queensland box, brush boxAn Australian hardwood at about 2,000 Janka with a fine, even texture and soft greyish-pink to russet tones. Its gentle grain suits a calm, uniform look.
Buckling Moisture: The extreme failure in which a floor lifts off the subfloor, caused by moisture, a missing expansion gap, or both. It usually means the floor must be partly reinstalled.

C

Calcium chloride test Moisture: An older slab-moisture test that measures the rate of moisture vapour emitting from a concrete surface. It is still referenced but is increasingly replaced by in-situ relative humidity testing. Source: ASTM F1869
CARB2 Standards: The California Air Resources Board's Phase 2 limits on formaldehyde emissions from composite wood products, such as the plywood and fibreboard cores in flooring. CARB2 became the de facto North American benchmark and was later mirrored in federal rules. Source: CARB
CDPH Standard Method Standards: The California Department of Public Health's chamber-test method (version 1.2, also known as Section 01350) for measuring how much VOC a product emits into indoor air. It is the yardstick behind FloorScore and GREENGUARD Gold and is referenced by LEED. Source: CDPH
Ceramic tile Materials: A fired-clay tile finished with a glaze. It is water-resistant and hard, but generally softer and more porous than porcelain, making it better suited to walls and lighter-traffic floors. Source: ANSI A137.1
Character grade Wood: A deliberately rustic appearance grade that welcomes knots, colour variation, and mineral streaks. It is a design choice rather than a defect, often costs less than clearer grades, and hides everyday wear well.
Chevron Installation: A pattern similar to herringbone, but with the plank ends cut at an angle so they meet point to point in continuous V-shaped rows. The mitred cuts make it more exacting to install than herringbone.
Chinese Birch Betula spp. Species: Also sold as: Asian birchBirch grown or milled in China, genuine birch of the genus Betula but often supplied as engineered veneer or plywood and in variable grades. The label tells you the region and processing more than it guarantees quality, and it is generally softer and less consistent than premium North American birch.
CITES Standards: The international treaty, the Convention on International Trade in Endangered Species, that restricts or documents trade in threatened plants and animals, including certain tropical timbers such as some rosewoods. It can affect whether an exotic species may be legally imported. Source: CITES
Click-lock Anatomy: A tongue-and-groove-style joint engineered to snap together without glue or nails, enabling floating installation. Variants include angle-tap and drop-lock mechanisms, and the quality of the locking profile strongly affects how tight and durable the seams stay.
Common grade Wood: Lumber and flooring grades, such as No. 1 and No. 2 Common, that permit more knots, streaks, and colour variation than Select grades. Common describes appearance, not defectiveness. Source: NHLA
Concrete densifier Materials: A chemical applied to concrete that reacts to harden and dust-proof the surface, a key step in creating a durable polished-concrete floor.
Core Anatomy: The middle structural layer that gives a plank its rigidity and stability. What the core is made of, whether HDF, SPC mineral, WPC foam, or plywood, largely determines how a floor handles moisture, temperature, and weight.
Cork Quercus suber Materials: A resilient floor made from the bark of the cork oak, prized for softness underfoot, warmth, and sound absorption. It is comfortable and renewable, but dents more easily than harder floors and needs a protective finish.
Cork underlayment Installation: A natural, renewable underlayment valued for sound damping and a firm, stable feel. It resists mould and compression well, but because it is organic it is usually paired with a moisture barrier over concrete.
Cradle to Cradle Standards: A certification that rates products on material health, reuse, renewable energy, water, and social fairness for a more circular life cycle. Higher levels signal a more sustainable, recyclable product. Source: C2C PII
Crowning Moisture: The opposite of cupping: the centre of a board rises above its edges, often after a cupped floor is sanded flat too soon or dries unevenly.
Cupping Moisture: When the edges of a board rise higher than its centre, forming a shallow U. It is a classic sign of excess moisture from below or high room humidity.

D

DCOF Tile: Dynamic Coefficient of Friction, the standard measure of how slip-resistant a tile is when wet. The North American tile standard sets a common benchmark of DCOF 0.42 or greater for level interior floors expected to get wet, though that is a guideline rather than a guarantee of safety. Source: ANSI A326.3
Declare label Standards: An ingredient disclosure, often called a nutrition label for building products, from the International Living Future Institute. It lists what a product contains and whether it includes any Red List chemicals. Source: ILFI
Delamination Moisture: When a floor's bonded layers separate, such as a wood veneer lifting from its core or a finish peeling away. It is usually caused by moisture, excess heat, or adhesive failure.
Delta IIC Performance: The number of impact-sound points a single underlayment adds to a bare concrete slab when tested on its own. It lets you compare underlayments directly: a Delta IIC of 20 means that product raised the slab's IIC rating by 20 points. Source: ASTM E2179
Dent resistance Performance: How well a floor resists permanent indentations from heavy or sharp loads. It tracks with material hardness: a hard species or dense core dents less than a soft or foamed one.
Dimensional stability Performance: A floor's resistance to expanding, contracting, or warping as temperature and humidity change. Higher stability, as in engineered wood or SPC, means fewer gaps, less buckling, and wider installation options.
Distressed Finish: A surface intentionally aged with dents, wear marks, and texture to mimic an old, well-used floor. Like hand-scraping, it also helps hide real-life scratches.
Domestic vs exotic species Wood: Domestic species such as oak, maple, hickory, and walnut are grown in North America and are generally easier to source and match; exotic species are imported for distinctive colour and often greater hardness. Price, availability, and responsible-sourcing questions differ between the two.
Douglas Fir Pseudotsuga menziesii Species: A softwood, about 660 Janka, common in older North American homes for its warm amber colour and vertical grain. It dents easily, so original fir floors are usually valued for character rather than hardness.
Dye lot Measurement: A production run of flooring with a specific colour and texture batch. Boxes from different dye lots can vary subtly, so professionals buy enough of one lot up front and check batch numbers before installing.

E

Eastern White Pine Pinus strobus Species: A very soft wood at about 380 Janka, used for wide-plank, rustic, and reclaimed looks. It dents and marks readily, developing a lived-in patina many owners prize.
Electric radiant heat Installation: In-floor heating that uses electric resistance mats or cables under the floor. It is easy to add in a single room such as a bathroom, but costs more to run than hydronic for large areas.
Embossed-in-register (EIR) Anatomy: A texturing process that aligns the surface embossing precisely with the printed grain beneath it, so the texture you feel matches the wood grain you see. EIR is a sign of a more realistic vinyl or laminate.
Engineered hardwood Materials: A floor built in layers: a real hardwood top (the veneer) bonded over a plywood or fibreboard core whose grain runs in alternating directions. That cross-layered build makes it far more dimensionally stable than solid wood, so it tolerates humidity swings and can often be installed over concrete or below grade. It can be refinished only as many times as its veneer allows. Source: NWFA
EPD (Environmental Product Declaration) Standards: A third-party-verified document, based on a life-cycle assessment, that discloses a product's environmental footprint, much like a nutrition label for its impact. An EPD reports impact; it does not by itself certify a product as green. Source: ISO 14025
Epoxy floor Materials: A resin coating troweled or rolled over concrete to create a seamless, chemical- and water-resistant surface, common in garages, workshops, and commercial kitchens.
EVA underlayment Installation: An ethylene-vinyl acetate foam underlayment that is softer and cheaper than IXPE but lower in density and more prone to compressing over time, which can stress click-lock seams. It offers less moisture and sound performance, so it best suits lighter-duty or budget installations.
Exotic hardwood Wood: Imported tropical species, from regions such as South America, Australia, Africa, and Southeast Asia, chosen for distinctive colour and often exceptional hardness. Buyers should weigh their higher price, greater colour change over time, and sourcing and sustainability questions.
Expansion gap Installation: The deliberate space left between a floor and the walls and fixed objects so the floor can expand and contract with humidity without buckling. It is normally hidden under baseboard or quarter-round.

F

FAS Wood: Short for First and Seconds, the highest standard lumber grade in the NHLA rules, denoting long, wide, and largely clear boards. It is a lumber-grading term you will see referenced in hardwood specifications. Source: NHLA
Figure Wood: Decorative grain patterns beyond ordinary straight grain, such as curly, birdseye, flame, or ribbon. Figured boards are prized and priced accordingly.
Floating floor Installation: An installation where planks lock to each other but not to the subfloor, floating over an underlayment. It is fast, forgiving, and reversible, but needs an expansion gap and a flat subfloor to perform well.
FloorScore Standards: An indoor-air-quality certification for hard-surface flooring and adhesives, showing a product meets strict VOC-emission criteria. It is administered by SCS Global Services in partnership with the Resilient Floor Covering Institute (RFCI). Source: RFCI / SCS Global
Formaldehyde Standards: A colourless gas that can off-gas from the adhesives in some composite wood cores. Emission limits under CARB2 and TSCA Title VI exist to cap it; look for compliance labelling on engineered wood, laminate, and their cores. Source: CARB / US EPA
FSC (Forest Stewardship Council) Standards: A certification showing wood or bamboo comes from responsibly managed forests. The FSC label is the most recognised mark of sustainable sourcing to look for on flooring. Source: FSC
Fumed wood Finish: Wood darkened by exposing it to ammonia vapour, which reacts with the tannins in species like oak to deepen the colour throughout rather than just on the surface. It is also called smoked.

G

Gapping Moisture: Visible spaces opening between boards, usually in dry seasons as wood loses moisture and shrinks. Minor seasonal gapping can be normal; persistent large gaps point to an acclimation or humidity problem.
Garapa Apuleia leiocarpa Species: Also sold as: Brazilian oak, grapia (not a true oak)A golden-yellow South American wood, sometimes sold as Brazilian oak, at about 1,700 Janka with a fine, even grain. It is not related to true oak.
Genuine Mahogany Swietenia macrophylla Species: Also sold as: Honduran / American mahoganyThe classic reddish-brown cabinet wood, softer than its reputation at about 800 Janka. It is valued for colour and stability rather than hardness, and true mahogany is increasingly restricted in international trade.
Glue-down Installation: An installation that bonds each plank or tile directly to the subfloor with adhesive. It is stable and quiet underfoot and common for tile and many commercial vinyls, but it is labour-intensive and harder to remove.
Granite Stone: An igneous natural stone, very hard at about 6 to 7 on the Mohs scale and low in porosity, which makes it one of the most durable and stain-resistant stone floors and suitable for heavy traffic. It needs only occasional sealing and resists acids and scratching far better than softer stones such as marble.
GREENGUARD Standards: A certification, administered by UL, indicating a product meets limits on chemical emissions for better indoor air quality. GREENGUARD Gold is the stricter tier used for schools and healthcare settings. Source: UL
Grey Ironbark Eucalyptus paniculata Species: One of the hardest flooring timbers available, roughly 3,600 Janka, ranging from honey to dark chocolate with a tight grain. Its density makes it exceptionally durable underfoot.
Grout Tile: The cementitious or epoxy filler between tiles. It locks tiles in place, accommodates slight size differences, and, when properly sealed or epoxy-based, keeps water from reaching the substrate.

H

Hand-scraped Finish: A surface texture, applied by hand or machine, that mimics the worn, undulating look of old floors. It is an aesthetic choice that also helps disguise everyday scratches.
Hard Maple Acer saccharum Species: Also sold as: sugar maple, rock mapleAlso called sugar maple, a pale, fine-grained wood at about 1,450 Janka. It is very hard but tends to blotch when stained, so it is often left natural or lightly finished.
Hardwax oil Finish: A penetrating finish of blended oils and waxes that soaks into the wood for a natural, low-sheen look. It is easy to spot-repair but needs periodic re-oiling, unlike a surface polyurethane.
HDF (high-density fibreboard) Anatomy: The dense, engineered wood-fibre core used in laminate and some engineered floors. Its density gives laminate its rigidity and impact resistance, but as a fibre product it swells if it stays wet, which is why standard laminate is not waterproof. Source: ANSI
Heartwood vs sapwood Wood: Heartwood is the darker, denser wood from the centre of the tree; sapwood is the paler, younger wood near the bark. The mix affects a floor's colour and, in some species, its durability, and appearance grades often limit how much sapwood is allowed.
Herringbone Installation: A classic pattern in which rectangular planks meet at right angles in an interlocking zig-zag of Ls. It looks timeless but uses more labour and material, and usually a larger waste factor, than a straight lay.
Hickory Carya spp. Species: Also sold as: often blended and sold as hickory-pecanThe hardest common domestic species at about 1,820 Janka, with dramatic grain and wide colour swings from blond to brown. Its toughness makes it a favourite for homes with kids, pets, or heavy traffic.
HPD (Health Product Declaration) Standards: A standardized disclosure of what a product is made of and the known health hazards associated with those ingredients. Like an EPD, it reports information rather than passing or failing a product. Source: HPD Collaborative
Hydronic radiant heat Installation: In-floor heating that circulates warm water through tubing beneath the floor, heating a room gently and evenly. The floor above must be rated for radiant heat to avoid gapping or delamination.

I

IBC (International Building Code) Standards: The model code, published by the International Code Council, that jurisdictions adopt for commercial and multi-family construction. For flooring it is the usual source of the minimum airborne (STC 50) and impact (IIC 50) sound ratings required between dwelling units. Source: ICC
ICC (International Code Council) Standards: The body that publishes the model building codes most of North America adopts, including the International Building Code and the International Residential Code. Its codes set the baseline requirements, such as the minimum sound ratings allowed between dwelling units, that flooring in a given building must meet.
IRC (International Residential Code) Standards: The model code, published by the International Code Council, covering one- and two-family homes. It governs the structural and safety requirements a residential subfloor and floor assembly must satisfy. Source: ICC
IXPE underlayment Installation: A cross-linked polyethylene foam underlayment with a uniform, closed-cell structure. It resists moisture well and holds its thickness over time (a low compression set), and even in thin layers it delivers strong impact-sound performance, which makes it a common attached or separate pad beneath rigid-core vinyl.

J

Janka hardness Wood: A standard test of how well a wood species resists denting and wear, measured by the force needed to press a small steel ball halfway into the wood. Higher Janka numbers mean a harder, more dent-resistant species; it is the most common way to compare woods, though it does not capture scratch or moisture behaviour. Source: ASTM D1037
Jarrah Eucalyptus marginata Species: A rich crimson-to-burgundy hardwood from Western Australia at about 1,910 Janka, known for a deep colour that matures beautifully over time.

K

Knot Wood: The base of a former branch appearing as a round mark in a board. Knots add rustic character in lower and character grades but can be weak points, and clear grades largely exclude them.

L

Lamella Wood: Another name for the real-wood top layer, or veneer, of an engineered board.
Laminate Materials: A floor with a high-resolution printed image of wood or stone sealed under a hard clear melamine layer, pressed onto a high-density fibreboard core. It is scratch-resistant and budget-friendly, but the core is fibreboard, so standard laminate is vulnerable to standing water unless it is specifically rated water-resistant. Source: NALFA
LEED Standards: Leadership in Energy and Environmental Design, the green-building rating system from the US Green Building Council. Low-emitting, certified flooring can contribute points toward a building's LEED certification. Source: USGBC
Limestone Stone: A soft, porous sedimentary stone at about 3 to 4 Mohs with a subtle, uniform appearance. It is acid-sensitive and absorbs stains readily, so it requires regular sealing and gentler care than granite or quartzite.
Linear foot Measurement: A measure of length regardless of width, used to price trim, mouldings, and some plank products. It is not the same as a square foot.
Linoleum Materials: A resilient floor made from linseed oil, cork or wood flour, and other largely natural materials. It is often confused with vinyl but is chemically unrelated: its colour runs through the whole material rather than sitting in a printed layer.
Lippage Tile: The height difference between two adjacent tiles, leaving one edge proud of its neighbour. Excess lippage is both a trip hazard and a sign of an uneven substrate or a rushed installation.
Live-sawn Wood: A cutting method that slices straight through the whole log, so a single board can show plainsawn, rift, and quartersawn grain together. It yields a full-character European look and uses the log efficiently.
Longboard Anatomy: An extra-long plank format that reduces the number of end joints across a room, giving a cleaner, more expansive look. Longboard describes a plank's proportions, not a material.
Loose-lay vinyl Installation: Heavier vinyl planks or tiles that stay put by weight and friction, sometimes with adhesive only around the perimeter, rather than clicking together or fully gluing down. They are easy to install and swap out, but need a very flat, clean subfloor.
Luxury vinyl (LVT/LVP) Materials: A multi-layer synthetic floor, sold as luxury vinyl tile (LVT) or plank (LVP), with a printed design under a clear vinyl wear layer. It is fully water-resistant, comfortable underfoot, and made in flexible or rigid-core forms. The word luxury refers to the realistic look and thicker build versus older sheet vinyl, not to any premium material.

M

Marble Stone: A metamorphic stone, essentially recrystallized limestone, prized for its veining but relatively soft at about 3 to 4 Mohs and sensitive to acids, so spills such as citrus or wine can etch it. It needs regular sealing and suits lower-traffic floors and accents more than busy kitchens.
Massaranduba Manilkara bidentata Species: Also sold as: Brazilian redwood, bulletwoodAlso called Brazilian redwood, a very dense exotic at about 3,190 Janka with deep red colour. Its hardness and weight make it durable but heavy to work with.
Melamine wear layer Laminate: The clear, resin-based top layer that protects a laminate's printed design. It is what gives laminate its hardness and scratch resistance.
Merbau Intsia bijuga Species: Also sold as: kwila, ipilA reddish-brown tropical hardwood at about 1,900 Janka, common in Australasia and valued for stability. It can bleed dark tannins when wet, so installers take care around moisture.
Micro-topping Materials: A thin cementitious overlay spread over existing concrete to renew or resurface it, giving a fresh, decorative finish without pouring a new slab.
Mil Measurement: A unit equal to one-thousandth of an inch (0.001 inch), used to state the thickness of a vinyl wear layer. A mil is not a millimetre, and confusing the two is a common buying mistake, since one mil is only about 0.025 mm.
Mineral streak Wood: A dark grey, green, or brown streak caused by minerals the living tree absorbed. It is a natural character mark, welcomed in rustic grades and limited in cleaner ones.
Moisture content Moisture: The percentage of water within a wood floor or subfloor. Installing wood outside the recommended moisture range, or with too large a gap between the flooring's and the subfloor's readings, invites cupping and gapping. Source: NWFA
Mortar bed (mud set) Tile: A traditional thick-bed method that sets tile into a packed bed of mortar rather than a thin layer of adhesive. It lets the installer build slope, as in a shower floor, and correct an uneven substrate.
Mosaic tile Tile: Small tiles, typically two inches or less and often mounted on mesh sheets, used for detail, borders, and shower floors. Their many grout lines add underfoot grip but also more grout to seal and clean.
MVER Moisture: Moisture Vapor Emission Rate, the result of a calcium chloride slab test, expressed in pounds of moisture per 1,000 square feet over 24 hours. Each flooring type specifies a maximum MVER it may be installed over. Source: ASTM F1869

N

Nail-down Installation: The traditional method for solid hardwood over a wood subfloor, fastening each board with flooring nails or cleats. It creates a solid, time-tested floor but requires a suitable wood subfloor.
NALFA Standards: The North American Laminate Flooring Association, which runs laminate performance testing and certification so buyers can compare products against a common standard. Source: NALFA
Natural stone Materials: Flooring cut from quarried stone such as marble, granite, slate, travertine, or limestone. Each piece is unique and long-lasting, but most stone is porous and needs sealing, and hardness and acid-sensitivity vary widely by type.
NFCA Standards: The National Floor Covering Association, a Canadian body that publishes installation standards and best practices used across the Canadian floor-covering trade. Source: NFCA
NHLA grading Wood: The rulebook, maintained by the National Hardwood Lumber Association, that defines how North American hardwood lumber is graded by the amount of clear, usable wood in a board. It is the reference behind most hardwood appearance grades. Source: NHLA
NOFMA Wood: The mill-grading and manufacturing standards for solid wood flooring, originally from the National Oak Flooring Manufacturers Association and now administered under the NWFA. NOFMA grades speak to how a solid wood floor is milled and sorted. Source: NWFA/NOFMA
Nominal vs actual size Measurement: The difference between a floor's labelled size and its true measured size. Tiles and planks are often sold at a rounded nominal dimension, so confirming the actual size matters when planning layout and grout lines.
NWFA Standards: The National Wood Flooring Association, a US trade body whose installation, sand-and-finish, and moisture guidelines are the most-cited best practices for wood flooring in North America. Source: NWFA

O

Off-gassing Standards: The release of volatile chemicals, such as VOCs and formaldehyde, from new materials into the air, usually strongest when a product is first installed. Certifications like FloorScore and low-VOC finishes exist to limit it.

P

Patagonian Rosewood Anadenanthera colubrina Species: Also sold as: curupay, cebil, angico (not a true rosewood)An extremely hard, dramatically striped South American wood sold as rosewood but unrelated to the true rosewoods of the Dalbergia genus. Another case where an exotic marketing name overstates the botanical reality.
Peel-and-stick vinyl Installation: Thin vinyl tiles or planks with a factory-applied adhesive backing that press directly onto a clean, flat subfloor. They are the cheapest and most DIY-friendly vinyl, but also the least durable and the most sensitive to subfloor flaws and moisture.
PEI rating Tile: A five-class scale, PEI I to V, rating a glazed tile's resistance to surface abrasion. PEI I to II are wall or light-use tiles; PEI III suits typical residential floors; PEI IV to V handle heavier and commercial traffic. Source: ASTM C1027 / ANSI A137.1
Penetrating oil finish Finish: A finish that soaks into the wood rather than forming a film on top, giving a very natural feel and matte look. It shows the grain beautifully but offers less surface protection and needs more upkeep than film finishes.
Phthalate-free Standards: Made without ortho-phthalate plasticizers, a chemical family once common in flexible vinyl. Most reputable flooring vinyl sold in North America is now phthalate-free, a point makers highlight for indoor-air and health reasons.
Plainsawn Wood: The most common and economical way boards are cut from a log, producing the familiar looping cathedral grain. Also called flatsawn, it shows more grain movement and expands slightly more across its width than quarter- or rift-sawn wood.
Plank Anatomy: A long, narrow flooring board, as opposed to a square tile. Plank width and length are style choices that also affect installation and how busy a finished floor looks.
Polished concrete Materials: A concrete slab mechanically ground and polished to a smooth, often glossy finish and hardened with a densifier. It is extremely durable and low-maintenance, though hard and cold underfoot.
Polyurethane finish Finish: A durable clear top coat for wood floors, available water-based, which is clearer, lower-odour, and fast-drying, or oil-modified, which adds a warmer amber tone but dries more slowly. It is the most common protective finish on site-finished floors.
Porcelain tile Materials: A denser, harder tile fired from refined clays at higher temperatures, with a water absorption of 0.5% or less, the threshold that separates porcelain from ceramic. Its low porosity suits wet areas, heavy traffic, and, in many climates, outdoor use. Source: ANSI A137.1
Prefinished vs site-finished Finish: Prefinished floors arrive with their stain and finish already factory-applied and cured; site-finished floors are sanded, stained, and coated after installation. Prefinished is faster and more consistent, while site-finished allows custom colour and a perfectly flat, seamless surface.
Purpleheart Peltogyne spp. Species: Also sold as: amaranth, violet woodA novelty exotic at about 2,520 Janka that is naturally purple, a colour that deepens with age and light. It is usually used as an accent rather than a whole floor.

Q

Quarter round Installation: A slim, rounded trim, also called shoe molding, installed where the floor meets the baseboard to conceal the expansion gap at the edge of the room.
Quartersawn Wood: Boards cut so the growth rings meet the face at a steep angle, yielding a straight, tight grain and often dramatic ray fleck in oak. Quartersawn wood is more dimensionally stable but wastes more of the log, so it costs more.
Quartzite Stone: A very hard metamorphic stone at about 7 Mohs, formed from sandstone, that rivals granite for durability and stain resistance while offering marble-like veining. Be aware that some softer stones are sold as quartzite; true quartzite is among the toughest natural-stone floors.

R

R-value Performance: A measure of a material's resistance to heat flow, where a higher number means more insulating. It matters for floors over cold slabs and with radiant heat, since a high-R-value floor can slow the warmth coming through.
Radiant-heat compatible Installation: A floor rated by its maker for installation over in-floor hydronic or electric heating. Not all floors qualify; the concern is how the material handles repeated warming and cooling without gapping or delaminating.
Random length Measurement: Flooring supplied in a mix of board lengths rather than one uniform size, which lets an installer stagger end joints naturally for a more authentic look.
Reclaimed wood Wood: Flooring milled from salvaged timber such as old barns, factories, or beams, valued for its history, patina, and character. It is sustainable and one of a kind, but variable supply, unknown moisture history, and hidden fasteners make it more demanding to work with.
Rectified edge Tile: A tile whose edges are mechanically ground to an exact, uniform size after firing, allowing very thin, crisp grout lines. Non-rectified, or cushioned-edge, tiles need slightly wider grout to absorb size variation.
Red Grandis Eucalyptus grandis Species: Also sold as: rose gumA plantation-grown eucalyptus marketed as a sustainable, fast-renewing hardwood with a warm pinkish tone. It is softer than the dense native Australian eucalypts and valued more for its eco credentials than for extreme hardness.
Red List Standards: The International Living Future Institute's list of chemicals it considers worst-in-class for human and environmental health. Products free of them can advertise Red List compliance. Source: ILFI
Red Oak Quercus rubra Species: The benchmark North American hardwood, about 1,290 on the Janka scale. Its open, forgiving grain takes stain evenly and hides wear, which is why red oak is the reference every other species is compared against.
Reducer Installation: A transition molding that tapers from a thicker floor down to a thinner or lower adjacent surface, for example from laminate to vinyl or tile.
Refinishing Finish: Sanding a wood floor down to bare wood and applying new stain and finish. Only solid and thicker-veneer engineered floors can be refinished, and only a limited number of times, which is why veneer thickness matters so much.
Relative humidity (RH) test Moisture: The current standard for measuring moisture in a concrete slab, using in-situ probes placed inside the slab to read the humidity deep within it. Meeting the flooring maker's RH threshold before installing is the best defence against moisture failures. Source: ASTM F2170
Riftsawn Wood: Boards cut at an angle that produces a very straight, uniform grain with no fleck. Rift and quartersawn boards are often sold together for their stability and clean, linear look.
Rigid core Materials: Any resilient floor built on a stiff, dimensionally stable core, chiefly SPC and WPC. Rigid-core planks resist telegraphing and temperature-driven movement far better than flexible glue-down vinyl, which is why most click-together vinyl sold today is rigid core.
Rubber flooring Materials: A resilient floor in sheets or tiles, made from natural or recycled rubber, valued for cushioning, slip resistance, and durability in gyms, playrooms, and commercial spaces.
Running bond (stagger) Installation: The common brick-lay layout where each row's end joints are offset from the row before, usually by a third or half a plank. A good stagger looks natural and adds strength; too little offset creates the stair-step or H-joint look installers try to avoid.

S

Santos Mahogany Myroxylon balsamum Species: Also sold as: cabreuva, balsamo (not a true mahogany)A dense South American wood at about 2,200 Janka with rich reddish-brown colour. Despite the name it is not a true mahogany, and it is far harder than genuine mahogany.
Sapele Entandrophragma cylindricum Species: An African hardwood at about 1,410 Janka resembling mahogany, often showing a lustrous ribbon figure on quartersawn boards.
Scratch resistance Performance: How well a floor's surface resists visible scratches from grit, pets, and furniture. It depends on the wear layer or finish rather than the core, and no floor is truly scratch-proof.
Screen and recoat Finish: A light refresh that abrades, or screens, the existing finish and adds a fresh top coat without sanding to bare wood. It renews a tired finish quickly, but only while the wear layer is still intact.
Select & Better Wood: A common appearance grade indicating wood with minimal knots and limited colour variation, giving a cleaner, more uniform look. The term comes from the grading rules and is not a guarantee about a board's strength. Source: NHLA
Self-leveling compound Installation: A pourable cement-based mix that flows out to fill low spots and create a flat subfloor. Flatness tolerance matters: most floors specify a maximum deviation, for example 3/16 inch over 10 feet, that leveling is used to achieve.
Sheen Finish: The gloss level of a floor's finish, from high-gloss through satin to matte. Lower sheens hide scratches, dust, and footprints far better than gloss, which is why they dominate today.
Sheet vinyl Materials: Vinyl flooring sold in wide continuous rolls rather than planks or tiles. Its seamless or nearly seamless coverage makes it highly water-resistant and inexpensive, which is why it remains common in bathrooms and laundry rooms.
Silver Maple Acer saccharinum Species: Also sold as: soft mapleA soft maple, distinct from hard (sugar) maple, that some mills, including in Quebec, cut for flooring. At roughly half the hardness of hard maple it dents more easily, so it matters whether a floor sold simply as maple is the hard or the soft kind.
Slate Stone: A fine-grained metamorphic stone, often laid with its naturally split, textured cleft face, which gives good slip resistance. Slate is durable and fairly low in porosity, though lower grades can flake, a defect known as spalling.
Soft Maple Acer rubrum / Acer saccharinum Species: Also sold as: red maple, silver mapleAn umbrella term for maples softer than sugar maple, chiefly red and silver maple. It is sometimes sold plainly as maple, so a buyer who wants the harder, more dent-resistant floor should confirm it is hard (sugar) maple.
Solid hardwood Materials: A floor milled from a single, solid piece of a hardwood species such as oak, maple, or walnut, typically 3/4 inch thick. Its great advantage is longevity: it can be sanded and refinished many times across decades. Because it is 100% wood, it also moves the most with humidity, so it is generally not recommended below grade or directly over concrete without added precautions. Source: NWFA
Sound rating (IIC) Performance: Impact Insulation Class, a rating of how well an assembly blocks impact sound such as footsteps and dropped objects. Codes and many condominium associations require IIC 50 or higher, which is why hard floors over occupied units usually need an acoustic underlayment. Source: ASTM E492
Sound rating (STC) Performance: Sound Transmission Class, a rating of how well a floor-and-ceiling assembly blocks airborne sound such as voices, television, and music. Building codes commonly require STC 50 between dwelling units, and a higher number means a quieter space. Source: ASTM E90
SPC (stone-plastic composite) Materials: A rigid-core luxury vinyl whose core blends powdered limestone with PVC and stabilizers. The dense mineral core makes SPC hard, dimensionally stable, and good at hiding minor subfloor imperfections; it feels firmer and sounds harder underfoot than WPC.
Spotted Gum Corymbia maculata Species: A tough Australian eucalypt at about 2,470 Janka, with flowing grain and colours from pale tan to rich chocolate. It is a mainstay of Australian flooring.
Square footage Measurement: The area a floor must cover, calculated as length times width for each room and summed. It is the starting point for every order, before a waste factor is added.
Stair nose Installation: A shaped trim piece that caps the exposed front edge of a stair tread, giving a finished, safe, rounded edge that matches the floor.
Staple-down Installation: A fastening method similar to nail-down that uses staples instead of cleats to secure boards to a wood subfloor.
Static load rating Performance: The maximum sustained weight a resilient floor can bear, from a heavy appliance or cabinet, without permanent indentation. It is an easily overlooked spec for kitchens and laundry rooms.
Stone and grout sealer Tile: A penetrating or topical treatment that reduces how much a porous stone or cement-based grout absorbs water and stains. Most natural stone and cement grout needs periodic resealing, and how often depends on the material and the traffic it sees.
Strand-woven bamboo Phyllostachys edulis (moso) Materials: Bamboo fibres shredded and compressed under heat and resin into planks that are extremely hard, often testing above 3,000 on the Janka scale. Remember that bamboo is a grass, and real-world performance depends heavily on manufacturing quality.
Subfloor Installation: The structural surface a finished floor is installed over, typically plywood or OSB over joists, or a concrete slab. Its flatness, dryness, and soundness set the ceiling for how well any floor can perform.
Sucupira Bowdichia / Diplotropis spp. Species: Also sold as: tento, sucupira pretaA hard Brazilian species at about 2,140 Janka, warm brown with fine light lines running through the grain.

T

Taber abrasion test Laminate: The abrasion test at the heart of a laminate's AC rating: weighted abrasive wheels spin against the surface until the printed decor layer wears through, and the rotation count sets the AC class. Source: EN 13329
Tallowwood Eucalyptus microcorys Species: A dense Australian eucalypt at about 1,900 Janka, yellow-brown with subtle olive-green hints, well suited to high-traffic and commercial floors.
Tannin bleed Wood: Dark staining that some species, such as oak and merbau, release when they get wet, which can mark grout, finishes, or nearby materials. It is a reason to control moisture during and after installation.
Tasmanian Oak Eucalyptus regnans / obliqua / delegatensis Species: Also sold as: Victorian ash, mountain ash (not a true oak)A marketing name for a group of three Australian eucalypts, not a true oak, pale in colour and moderate in hardness at about 1,350 Janka. It stains and finishes readily.
Teak Tectona grandis Species: Also sold as: Burmese teakA legendary tropical hardwood at about 1,070 Janka, gold-brown and rich in natural oils that give outstanding water and rot resistance. True Burmese teak is prized and costly, and many products labelled teak are actually other species.
Telegraphing Performance: When bumps, ridges, or seams in the subfloor show through to the finished floor surface. Flatter subfloors and stiffer, rigid-core products reduce it.
Terracotta Tile: A rustic, unglazed fired-clay tile whose name means baked earth. It is warm in colour and highly porous, so it must be sealed to resist stains and moisture; Saltillo is a well-known handmade terracotta.
Terrazzo Stone: A composite floor of marble, glass, or stone chips set in a cement or epoxy binder, then ground and polished smooth. Poured in place or supplied as tiles, it is extremely durable and seamless, and has enjoyed a strong design revival.
Thermal expansion Performance: The tendency of a floor, especially vinyl, to expand and contract with temperature changes such as strong sunlight. It is why rigid vinyl needs expansion gaps and why some floors are not recommended in sunrooms.
Thinset Tile: The cement-based mortar that bonds tile to the subfloor or backer board. Correct thinset coverage is critical: voids beneath a tile are a leading cause of cracks and hollow spots.
Tigerwood Astronium spp. Species: Also sold as: Goncalo alves, Brazilian koa, jobilloA striking exotic, also called Goncalo Alves, at about 2,160 Janka, with bold dark streaks over an orange-brown background. The dramatic striping mellows somewhat as it ages.
Tile Materials: A hard flooring unit, most often fired clay (ceramic or porcelain) or cut natural stone, set individually into an adhesive bed with grouted joints. Tile is valued for water resistance and durability; how it performs depends on the material, its ratings such as PEI, DCOF, and water absorption, and the quality of the substrate and installation beneath it.
Tile spacers Tile: Small plastic crosses or wedges placed between tiles to keep grout lines even and consistent during installation, then removed before grouting.
Tongue-and-groove Anatomy: The classic joint where a protruding tongue on one board fits a groove on the next, aligning boards and spreading load across the seam. It is the basis of both nailed and many glued installations.
Trade name Wood: Also sold as: marketing name, commercial nameAn evocative sales name for a wood that may not match its botanical species, such as Brazilian cherry (really Jatoba), Santos mahogany (not a mahogany), or Tasmanian oak (a eucalyptus, not an oak). Trade names sell a look; to know what you are actually buying, and how it will behave, check the botanical Latin name.
Transition strip Installation: A shaped trim piece that bridges two floors or covers an edge, such as a T-molding between rooms, a reducer down to a lower floor, or a threshold at a doorway. Transitions also hide the expansion gap at these boundaries.
Travertine Stone: A sedimentary stone, a form of limestone, with a distinctive pitted surface whose natural holes are usually filled and honed smooth. It is softer and more absorbent at about 4 to 5 Mohs, sensitive to acids, and needs sealing, making it best for moderate traffic and warm, classic looks.
TSCA Title VI Standards: The US Environmental Protection Agency rule that adopted CARB's Phase 2 formaldehyde limits nationwide for composite wood products. Compliant flooring is labelled TSCA Title VI compliant. Source: US EPA

U

Uncoupling membrane Tile: A layer installed between tile and subfloor that lets the two move independently, absorbing stress that would otherwise crack tile or grout. It is especially useful over concrete or wood that may shift.
Underlayment Installation: A thin cushioning layer rolled out beneath a floating floor for sound damping, comfort, and sometimes moisture protection. It is not the same as the subfloor, and the wrong underlayment can void a warranty or telegraph subfloor flaws.
UV-cured finish Finish: A factory finish hardened instantly under ultraviolet light, producing an extremely durable, consistent coating that is ready to walk on immediately. It is standard on many prefinished floors.

V

Vapor barrier Moisture: A sheet or coating that slows moisture from migrating up through a subfloor, especially concrete, into the floor above. Wood, laminate, and other moisture-sensitive floors over slabs usually require one; a vapor retarder is a lighter-duty version.
VCT (vinyl composition tile) Materials: A tile of vinyl blended with mineral fillers, common in schools and commercial buildings. It is durable and repairable but porous, so it needs periodic stripping, waxing, and polishing to stay sealed, a maintenance cycle most homeowners prefer to avoid.
Veneer Wood: On engineered hardwood, the top layer of real wood bonded to the core (also called the lamella). Its thickness, commonly 0.6 to 6 mm, decides how many times, if ever, the floor can be sanded and refinished, making it the spec that most affects an engineered floor's lifespan. Source: NWFA
VOC Standards: Volatile organic compounds, carbon-based chemicals that can evaporate from finishes, adhesives, and some floors into indoor air. Lower-VOC products and certifications such as FloorScore exist to limit what a floor contributes to indoor air quality.

W

Waste factor Measurement: The extra flooring bought beyond a room's exact square footage to cover cuts, mistakes, and future repairs, commonly about 5 to 10% and more for diagonal or herringbone layouts. Ordering too little risks a batch mismatch later.
Water absorption Tile: The percentage of water a fired tile absorbs, which defines its category: porcelain absorbs 0.5% or less, while ceramic absorbs more. Lower absorption means better suitability for wet areas and freeze-prone climates. Source: ASTM C373 / ANSI A137.1
Waterproof vs water-resistant Performance: Waterproof means the plank material itself is unharmed by water, as with solid vinyl or SPC, while water-resistant means it tolerates brief spills but can still be damaged by standing water or seepage through the seams. The distinction matters most in kitchens, baths, and basements.
Wear layer Anatomy: The clear protective top layer of a floor, and on most floors the single most important durability spec. On vinyl it is measured in mils (thousandths of an inch), roughly 6 to 12 mil for homes and 20 mil and up for commercial use; on engineered wood it is the real-wood veneer, measured in millimetres, which sets how often the floor can be refinished; on laminate it is a hard clear melamine coat.
Wenge Millettia laurentii Species: A very dark, near-black African hardwood at about 1,620 Janka with a coarse, striking grain. It is used for bold, contemporary floors and accents.
White Ash Fraxinus americana Species: A pale, resilient hardwood with bold, oak-like grain at about 1,320 Janka. Springy and shock-resistant, it is the traditional wood of baseball bats as well as floors.
White Oak Quercus alba Species: A harder, tighter-grained cousin of red oak at about 1,360 Janka, with cooler brown tones and better water and rot resistance. Its look and durability have made it one of the most requested wood floors of recent years.
Wide plank Measurement: Planks wider than the traditional strip, generally about five inches and up. Wider boards show fewer seams and more grain, but move more with humidity, so subfloor prep and acclimation matter more.
Wire-brushed Finish: A texture made by scraping the wood's soft grain away with wire brushes, leaving the harder grain raised. It adds subtle texture, hides scratches and everyday wear, and has become one of the most popular hardwood surfaces.
WPC (wood-plastic composite) Materials: A rigid-core luxury vinyl with a foamed polymer core. Despite the name, the wood is usually a wood-flour filler rather than solid wood. The foamed core makes WPC thicker, warmer, and softer underfoot than SPC, at the cost of some hardness and dent resistance.

Y

Yellow Birch Betula alleghaniensis Species: A smooth, light-toned hardwood at about 1,260 Janka that resembles maple at a lower price. Like maple, it can stain unevenly.

About this glossary: definitions are written by Flooring Institute in our own words; technical and regulated terms are attributed to the authority that defines them. We are not a certification or standards body — we explain theirs. Spotted an error? It gets treated as first-class work. Last verified: 21 July 2026.