Glossary of Industry Terms




Formerly an earthenware with an opaque luster glaze and overglaze colored decorations, but currently designating any decorated earthenware having an opaque glaze. (ASTM C 242).

Marble mosaic tile

Tile made of small marble tesserae that vary slightly in size, usually about one half inch square and mounted on sheets of paper to facilitate installation. (CTI)

Marble tiles

Marble cut into tile sizes twelve (12) inches square.-or less, usually % inch to 3/a inch thick. Several types of finishes are made, polished, honed, split faced, etc.

Masking power

The ability of a fired glaze to mask visually the body on which it is applied. (ASTM C 242).

Master Grade certificate

A certificate that states tile listed in the shipment and described on the certificate are made in accordance with TCA 137.1-76. Mastic. Organic file adhesive.

Mastic grout

A chemical mixture of organic and inorganic ingredients forming a one part grouting composition that is used directly from the manufacturer’s container.

Mat glaze

A colorless or colored ceramic glaze having low gloss. (ASTM C 242).
Maturing range. The time-temperature range within which a ceramic body, glaze, or other composition may be fired to yield specified properties. (ASTM C 242-72)

Medium duty tile

Tile suitable for pedestrian traffic such as entryways in multiple dwellings and lobbys. Melt. To change a solid into a liquid by the application of heat; or the liquid resulting from such action. (ASTM C 242).

Metal quarry tile rack

Metal quarry tile racks are available in many patterns, and they can be made to order for special patterns. They are used to maintain the same width between the quarry tiles.

Mexican paver tile

Terra cotta-like tile, used mainly for floors, and handmade. These tile vary in color, texture and appearance, from tile to tile and within each tile. They are available in squares up to 12 inches, hexagon, octagon, elongated hexagon, fleur de lis and other shapes. These tile are coated with various types of sealers because of their soft absorptive characteristics. The coatings provide a wearing surface on the pavers which would otherwise powder away under wear. (CTI)

Mill scale

The oxide layer formed during the hot rolling of metals, such as that formed on hot-rolled reinforcing bars.

Mineral aggregate

Aggregate consisting essentially of inorganic nonmetallic materials.


The act or process of mixing; also mixture of materials, such as mortar or concrete.


A machine used for blending the constituents of concrete, grout, mortar, cement paste, or other mixture.

Mixer, colloidal

A mixer designed to produce colloidal grout.

Mixer, horizontal shaft

A mixer having a stationary cylindrical mixing compartment, with the axis of the cylinder horizontal, and one or more rotating horizontal shafts to which mixing blades or paddles are attached.

Mixer, nontilting

A horizontally rotating drum mixer that charges, mixes, and discharges without tilting.

Mixer, open-top.

A truck-mounted mixer consisting of a trough or a segment of a cylindrical mixing compartment within which paddles or blades rotate about the horizontal axis of the trough. (See also Mixer, horizontal shaft.)

Mixer, pan

See Mixer, vertical shaft.

Mixer plant

See Batch plant.

Mixer, tilting

A rotating drum mixer that discharges by tilting the drum about a ‘fixed or movable horizontal axis at right angles to the drum axis. The drum axis may be horizontal or inclined while charging and mixing.

Mixer, vertical shaft

A cylindrical or annular mixing compartment having an essentially level floor and containing one or more vertical rotating shafts to which blades or paddles are attached; the mixing compartment may be stationary or rotate about a vertical axis.

Mixer efficiency

The adequacy of a mixer in rendering a homogeneous product within a stated period; homogeneity is determinable by testing for relative differences in physical properties of samples extracted from different portions of a freshly mixed batch.

Mixing cycle

The time taken for a complete cycle in a batch mixer, i.e., the time elapsing between successive repetitions of the same operation (e.g., successive discharges of the mixer).

Mixing speed

Rotation rate of a mixer drum or of the paddles in an open-top, pan, or trough mixer, when mixing a batch; expressed in revolutions per minute (rpm), or in peripheral feet per minute of a point on the circumference at maximum diameter.

Mixing time

The period during which the constituents of a batch of concrete are mixed by- a mixer; for a stationary mixer, time is given in minutes from the completion of mixer charging until the beginning of discharge; for a truck mixer, time is given in good mixing in a specific mixing speed or expressed in terms of total revolutions at a specific mixing speed.

Mixing water

The water in freshly mixed sand-cement grout, mortar, or concrete, exclusive of any previously absorbed by the aggregate (e.g., water considered in the computation of the net water-cement ratio).


The assembled, blended, co-mingled ingredients of mortar, concrete, or the like; or the proportions for their assembly.

Modular ratio

The ratio of modulus of elasticity of steel E, to that of concrete E, usually denoted by the symbol n.

Modulus of deformation

A concept of modulus of elasticity expressed as a function of two time variables; strain in loaded concrete as a function of the age at which the load is initially applied and of the length of time the load is sustained.

Modulus of elasticity

The ratio of normal stress to corresponding strain for tensile or compressive stresses below the proportional limit of the material; referred to as “elastic modulus of elasticity”; “Young’s modulus,” and “Young’s modulus of elasticity”; denoted by the symbol E. (See also Modulus of rigidity.)
NOTE: Few materials conform to Hooke’s law throughout the entire range of stress-strain relations; deviations therefrom are caused by inelastic behavior. If the deviations are significant, the slope of the tangent to the stress-strain curve at the origin, the slope of the tangent to the stress-strain curve at any given stress, the slope of the secant drawn from the origin to any specified point on the stress-strain curve, or the slope of the chord connecting any two specified points on the stress-strain curve, may be considered as the modulus; in such cases the modulus is designated, respectively, as the “initial tangent modulus,” the “tangent modulus,” the “secant modulus”, or the “chord modulus”, and the stress stated. The modulus is expressed as force per unit of area (e.g., psi or Pa).
Modulus of rigidity. The ratio of unit shearing stress to the corresponding unit shearing strain; referred to as “shear modulus” and “modulus of elasticity in shear”; denoted by the symbol G. (See also Modulus of elasticity.)

Modulus of rupture

A measure of the ultimate loadcarrying capacity of a beam and sometimes referred to as “rupture modulus” or “rupture strength”. It is calculated for apparent tensile stress in the extreme fiber of a transverse test specimen under the load which produces rupture. (See also Flexural strength.)
NOTE: The actual stress in the extreme fiber is less than the apparent stress since the flexure formula employed in the calculation is valid only for stresses within the proportional limit of the material; nevertheless. the nominal rupture strength so obtained is considered the rupture modulus.

Modulus of subgrade reaction

Ratio of load per unit area of horizontal surface (of a mass of soil) to corresponding settlement of the surface; it is determined as the slope of the secant, drawn between the point corresponding to zero settlement and a specified point on the load-settlement curve obtained from a plate load test on a soil using a 30 in. or greater diameter loading plate.

Moist room

A room in which the atmosphere is maintained at a selected temperature (usually 23.0±1.7 C or 73.4±3.0 F) and a relative humidity of at least 98 percent, for the purpose of curing and storing cementitious test speciment; the facilities must be sufficient to maintain free moisture continuously on the exterior of test specimens.

Moisture expansion

An increase in dimension or bulk volume of a ceramic article caused by reaction with water or water vapor. (ASTM C 242).
NOTE: This reaction may occur in time at atmospheric temperature and pressure, but is expedited by exposure of the article to water or water vapor at elevated temperatures and pressures.

Moisture movement

1. The movement of moisture through a porous medium; 2. The effects of such movement on efflorescence and volume change in hardened cement paste, mortar, concrete, or rock.


1. A divider containing a cavity into which neat cement, mortar, or concrete test specimens are cast; 2. A form used in the fabrication of precast mortar or concrete units (e.g., masonry units).

Mold oil

A mineral oil that is applied to the interior surface of a clean mold, before casting concrete or mortar
therein, to facilitate removal of the mold after the concrete or mortar has hardened. (See also Form oil, Bond breaker, and Release agent).


The colloquial expression for the more descriptive term bending moment.

Moment distribution

A method of structural analysis for continuous beams and rigid frames whereby successive converging corrections are made to an assumed set of moments until the desired precision is obtained; also known as the Hardy Cross method.

Monochrome decoration

A single color decoration. (ASTM C 242).

Monocottura (Single-Fired)

A term used for tile manufactured by a process which allows the simultaneous firing of the clay with the glaze producing a finished tile with a single firing.


A body of plain or reinforced concrete cast or erected as a single integral mass or structure. Monolithic concrete. Concrete cast with no joints other than construction.

Monolithic terrazzo

The application of a s/s in. (15 mm) terrazzo topping directly to a specially prepared concrete substrata, eliminating an underbed.

Monolithic topping

On flatwork: a higher quality, more serviceable topping course placed promptly after the base course has lost all slump and bleeding water. Monomer. An organic liquid, of relatively low molecular weight, that creates a solid polymer by reacting with itself or other compounds of low molecular weight or both.


Composed of single molecules; specifically, films that are one molecule thick. Denotes a thickness equal to one molecule (e.g., certain chemical compounds develop a “monomolecular film” over bleeding water at the surface of freshly placed concrete or mortar as a means of reducing the rate of evaporation).


See Montmorillonoid. Montmorillonoid. A group of clay minerals, including montmorillonoite, characterized by a sheet-like internal molecular structure; consisting of extremely finely divided hydrous aluminum or magnesium silicates that swell on wetting, shrink on drying, and are subject to ion exchange.


A mixture of cement paste and fine aggregate; in fresh concrete, the material occupying the interstices among particles of coarse aggregate; in masonry construction, mortar may contain masonry cement, or may contain hydraulic cement with lime (and possibly other admixtures) to afford greater plasticity and workability than are attainable with standard hydraulic cement mortar. (See also Cement, masonry and Masonry mortar).
Mortarboard. The mortarboard is used as a table to hold mortar. It is usually 30″ square.

Mortar hoe

The mortar hoe is used for hand-mixing mortar. The best type has a perforated blade and a handle about 66″ in length. The hoe should be kept clean and free of all mortar so it can be pushed and pulled easily through a box of mortar.

Mortar mixer

Most mortar mixers are driven by gasoline combustion engines of ll/_, horsepower or greater, depending on the type of sack mix. Electrically driven mixers are used when small batches of mortar are needed. The quality of machine-mixed mortar far exceeds that of hand-mixed mortar.

Mortar pumping machine

The mortar pumping machine is used with the mortar mixer. Mixed mortar is poured into the hopper, and a pneumatic gun forces the mortar through a hose. The mortar can be delivered through the hose to tilesetters working as high as 13 stories above the street. Admixtures are added to the mortar as a bonder so that the mortar in the hose will not separate. The plastering gun can be used on the hose, or the hose can be used as a hoist.


Small tile or bits of tile, stone, or glass. These are used to form a surface design or an intricate pattern.

Mounted tile

Tile assembled into units or sheets by suitable material to facilitate handling and installation. Tile may be face-mounted, back-mounted or edge-mounted. Face-mounted tile assemblies may have paper or other suitable material applied to the face of each tile, usually by water soluble adhesives so that it can be easily removed after installation but prior to grouting of the joints. Back-mounted tile assemblies may have perforated paper, fiber mesh, resin or other suitable material bonded to the back and/or edges of each tile which becomes an integral part of the tile installation. Back-mounted and edgemounted tile assemblies shall have a sufficient exposure of tile and joints surrounding each tile to comply with bond strength requirements.. Tile manufacturers must specify whether back-mounted and edge-mounted tile assemblies are suitable for installation in swimming pools, on exteriors and/or in wet areas.
Mud. A slang term for mortar.


A rare mineral of theoretical composition 3A1203 – 2Si02, a relatively stable phase in ceramics produced by the high temperature reaction of alumina and silica or by the thermal decomposition of aluminasilica minerals such as kyanite, sillimanite, andalusite, and various clay minerals. (ASTM C 21).

Mullite porcelain

A vitreous ceramic whiteware for technical application in which mullite (3A1,0,-2SiO,) is the essential crystalline phase. (ASTM C 242-72)

Mullite whiteware

Any ceramic whiteware in which mullite (3A1,0, – 2SiO,) is the essential crystalline phase. (ASTM C 242).


Tile installed in a precise area of a wall or floor to provide a decorative design or picture.  Glass or marble mosaic tile (tesserae) made to form a picture or design.

Ceramic tile, painted and fired to form a picture or design

See Decorated and Decoration.

Muriatic acid

Hydrochloric acid (30% HCL), commercial grade.