Tiles & Tiling Terminology

The A - Z of Tile Terms

Tile terminology can be confusing, especially when incorrect terms or generic terms are misrepresented or used incorrectly.  We have selected 50 terms and their meanings that users may encounter during the selection process. Relevant Australian Standard (AS) or International Standard (ISO) numbers are mentioned where applicable. The majority of the descriptions are taken from The Italian Ceramic Tile Dictionary, published by EDI-CER, the publishing arm of Assopiastrelle, the Italian Association representing the Italian tile sector.

Abrasion Resistance
The degree to which a floor tile's surface will withstand friction (the wear of foot traffic). Resistance is determined by abrasion tests. (AS 4459-7) classifies tiles from Group I (suitable for light residential traffic) to Group V (suitable for commercial traffic.)

Literally "two firings", referring to the separate firing of the clay body and the glaze. Bicottura glazes are not as scratch resistant and are now only used on walls.

Body (of tile)
The structural portion of a ceramic article such as the clay material or mixture, as distinct from the glaze.

Bullnose Tiles
Tiles featuring a rounded edge used to finish wall installations, turn outside corners or applied to the leading edge for some steps.

Chemical Resistance
The ability of a tile surface to withstand damage from chemical, acids, alkalis and swimming pool salts.

Clinker Tiles (also Klinker)
Natural clay tile, generally extruded and unglazed, vitrified or impervious to moisture and therefore suitable for indoor and outdoor use.

Coefficient of Friction
A measurement of slip resistance. Different standards apply to dry areas or those exposed to water or grease. Talk with your retailer about appropriate slip resistance for each area.

Colourway (s)
Simply describes the colours or colours in which certain products are available.

Cove Tiles
Cove trim tiles with rounded top edge, used to finish tile installation as baseboard, splashback, etc.

A fine, hair-line cracking which sometimes appears on the glazed face of a tile. Usually caused by tensile stress between tile body and glaze. May be intentionally produced for artistic effect.

Crystalline Finish
Extra thick glaze usually applied to small tiles for artistic effect.

Decorated Tile
Ceramic tiles that have been embellished by means of hand painting, silk screening, decals or other techniques.

Dust-pressed Tile
Tiles formed by the compaction of finely milled raw materials in moulds before firing. The majority of indoor tiles are produced this way.

Crystalline deposit that sometimes appears on the surface of grout joints or unglazed tiles as a whitish powder or crust, caused by moisture reacting with impurities in the mortar.

Resin material used in mortars and grout for thin-set tile installations.

Expansion Joint
Separation provided between adjoining parts of a structure to allow movement at stress points to prevent uncontrolled cracking.

Extruded Tiles
Tiles formed by the extrusion process wherein the still malleable or plastic raw clay is forced through a mould and then cut into shape before firing.

Textural or visual characteristics of a tile surface. For glazed tiles, this may be high gloss, lappato, satin or matt. Generally for porcelain tiles, finish can be natural, polished, honed, and anti-slip texture. Other finishes mimicking stone such as bush hammered are also available. Other effects include raised, embossed, dimpled, etched, scored, ribbed, etc.

Fire Resistance
Ability to withstand burning by flame. Ceramic tiles are fireproof at any temperature and will not release toxic emissions.

Final step of tile manufacturing process when raw material is ‘baked' at high temperature (up to 1250 degrees C for porcelain tiles) to harden the tile body and glaze (if present).

The size of ceramic tiles may very from 1x1cm to 60x120cm and larger. Format is a modern term that simply refers to size.

Frost Resistance
Ability of certain ceramic tiles to withstand freeze/thaw conditions with minimal effect. Frost resistance of ceramic tile is dependent on the tile's porosity and water absorption levels.

Glass Mosaic
Mosaic tiles composed entirely of glass, rather than ceramic material.

Glassy opaque or transparent coating fired or fused on to the ceramic tile body, creating a smooth, impermeable surface.

Glazed porcelain
Now the most popular type of indoor floor tile. The tile is made from porcelain clays but glazed for aesthetic effect. They are dense, strong and best cut with wet saw.

Grout Joint
Space left between tiles to be filled with grout. This space may be extremely narrow or wider depending on the required installation, type of tile and/or its aesthetics.

Impact Resistance
Ability of ceramic tile to resist breakage - either throughout the body or as surface chipping - as the result of a heavy blow. In general, ceramic tile is not a resilient material, and care should be taken to avoid dropping heavy or sharp objects on it's surface. Glazed tiles are more susceptible to surface chipping than unglazed tiles.

Small, sometimes decorative tiles used in combination with larger or plain tiles to create patterns. Small square inserts are also known as taco or tozzetto.

Jolly Tiles
Trim tiles mitred along one or two edges, used in corner and countertop installations. Also called angled (45 degree) tiles.

In finished installations, lippage refers to the condition where one edge of a tile is higher than an adjacent tile. Excessive lippage can cause trips and falls.

Modular Format
Combining different tile sizes is a popular trend which may be described as ‘modular'. Generally a mixture of sizes from the same tile series are laid together to create a more interesting pattern in the installed tiles.

Mohs' Scale
Scale used to express the measure of a material's hardness from Mohs' 1 (hardness of talc) to 10 (diamond).

Tiles produced with only one high temperature firing, generally with harder glaze and denser body than wall tiles with moisture absorption below 3 percent.

Single-fired tiles with higher porosity and water absorption levels than ‘monocottura' tiles.

Mosaic Tiles
Ceramic mosaic tiles are defined by their size. Generally less than 15cm square. Their composition is the same as ceramic tiles. They may be glazed or unglazed and mounted on mesh backing. Also available in glass and metal.

Nominal Size
The approximate size of tile face or thickness used for general purposes. Tile sizes can vary by up to plus or minus 3mm over a nominal 333mm long tile, depending on the batch supplied.

Pencil Tiles
Narrow rectangular tiles (e.g. 2x20cm) sometimes with rounded surface, used on walls as accent pieces.

Porcelain Stoneware
Dust-pressed ceramic tiles with water absorption levels less than 0.5% and high mechanical and chemical characteristics. The surface of these tiles may be glazed or unglazed. Often specified for exterior installations, they are also referred to as fully vitrified.

Volume of pores relative to volume of tile body and capable of absorbing moisture (and therefore stains).

Quarry Tiles
Traditional term for single extruded natural clay tiles with a water absorptions level not exceeding 6%. Can be glazed or unglazed.

Cutting or grinding the edges off a tile allows the dimensions and squareness to be precisely controlled. Typically exhibiting a very square edge, rectified tiles are generally suited for installing without spaces or obvious ground lines between the tiles.

Clear coating sometimes applied to unglazed floor tiles to protect the surface from grease spills or staining materials (also known as sealant).

Slip Resistant Tiles
Tiles treated to prevent slipping either by adding an abrasive grit to the glaze or a texture to the design of the tile surface structure such as ribs, studs etc.


Literally-the underlying surface. The surface upon which you are adhering tiles


Traditional clay used to produce unglazed, cream to red body tiles, generally extruded and 12mm thick or more. Surface may be rustic, smooth, polished, or waxed.

Thermal Shock Resistance
Ceramic tile's ability to resist alteration when subjected to rapidly fluctuating extreme temperatures.

Unglazed Tiles
Unglazed tiles derive their colour and texture from their raw materials or may be coloured by means of oxides dispersed throughout the body. They are generally fully vitrified.

Vitrified Tiles
Vitreous tiles absorb less than 3% moisture whereas Full Vitrified tiles are made from fine particles and fired to high temperatures (1250 degrees) which results in a denser tile with extremely low porosity (moisture absorption of less than 0.5 percent). Porcelain stoneware tiles are fully vitrified making a layer or glaze unnecessary for the tile to be impervious to water.

Generally add 10% to the amount required for wastage due to cutting etc. If the installation is complicated or a lot of cutting is involved, the amount for wastage may need to be increased to 15%.

Water Absorbtion
The quantity of water a tile can absorb expressed as a percent of the dry tile weight. High water absorption corresponds to a porous structure, while compact, vitrified structures feature low water absorption.