Abrash - Variations of density in a color seen in a carpet by irregular horizontal washes; caused by the wool being dyed at different times in different patches of a color, which is of unequal density. Although an accidental and therefore arbitrary process, abrash can greatly enhance the beauty of a carpet.

Alum - Double sulfate of aluminum and potassium used as a mordant.

Aniline - Chemical dye, a derivative of coal-tar. First produced in the 1860s and ubiquitous in the Middle East from the 1880s. Most frequently encountered in the red-blue-purple range, the substance being named after anil, the indigo plant. Colors are very fugitive; a bright orange-pink, for instance, will fade at the tip to walnut-brown.

Chrome dye - A fast synthetic dye mordanted with potassium bichromate. This, and other more recent synthetic colors, are now used in all the major rug weaving areas of the world. Although fast, the colors are harsh and dead.

Cochineal - Scarlet red similar to but more brilliant than lac. Obtained from the crushed bodies of an insect native to Mexico and the West Indies, and imported into Europe from the 16th century (but not into the Middle East until the end of the 18th century). Supposed until the 18th century to be the berry or seed of an oak.

Compound-weave - Technical term for pieces made with more than one set of either warp or weft elements, or both. Form of flat-weaving.

Damascene - Named after Damascus, this is a process of decorating steel by etching, inlaying gold or silver, or encrusting, so as to produce a watered effect. In old carpet literature, following European inventories of the 16th and 17th centuries, used to describe either Mamluk carpets or certain designs found on Anatolian pieces. Used either to describe the effect of the design or, as some scholars supposed, because it was believed that the carpets had originated in Damascus.

Djidjim - Refers to either a wall hanging/entrance hanging, or to a weaving technique in which flat-woven strips are joined together to form the completed piece.

Indigo - Blue dye obtained from the leaves of the indigo plant, one of the various species of Indigofera, a tropical genus of Papilionaceae. Native to India, from whence most of the leaves used in the preparation of the dye in Persia were exported. The dye was prepared from a fermented compound of crushed indigo leaves, red clay skip, potash, grape sugar, and slaked lime.

Kelim (kilim, khilim, kileem, gilim, ghilim, gelim, dilim, palas) - Form of flat-weaving associated principally with Anatolia. A kelim made in Thrace is called a Sharkyoy.

Kermes - Crushed female body of an insect which gives a red similar to cochineal and lac. The insect breeds on the Kermes oak (Quercus coccifera). Its use in carpets has never been satisfactorily established.

Lac (Laq) - Meaning literally 'hundreds of thousands'. Name given to a brilliant deep purple-red obtained from melting and straining the resinous excretions of the Tachardia lacca, a scale insect native to India which covers the twigs of certain trees in a resinous substance for the purpose of immuring the female of the species. The red dye, like that of a cochineal and kermes, is the extract of the female bodies of the insect, which in this case are garnered with the resin.

Lampas - A method of weaving so that the pattern is raised in relief against the ground. A form of embroidery.

Madder - Deep red-brown dye extracted from the root of the Rubia tinctorum or other Rubia plants.

Mina Khani pattern - Floral pattern said to have been named after Mina Khan, although this is certainly apocryphal. Repeat pattern of large palmettes and small white flowers contained in a lattice of stems. Stylized geometrical versions found in certain tribal carpets, such as those of the Baluchi.

Mordant - Chemical substance with which the wool is treated in order to fix the dye color. Can itself affect the eventual color and can be corrosive.

Pomegranate Rind - Gives a dull yellow dye.

Saph - Prayer rug with multiple mihrabs.

Sileh - Thought to be a corruption of a now unknown Caucasian place name. A form of Soumak, sileh usually refers to pieces woven with rows of large S-motifs thought to represent the dragon motif degenerated to virtual abstraction.

Soumak (Sumak, Summak, Sumacq, Sumakh). Thought to be a corruption of Shemaka, town in south-east Caucasus. Technique of progressive weft wrapping.

Tiraz - Official weaving factory usually set up under Royal Patronage.

Verneh (Verne) - Thought to be a corruption of a now unknown Caucasian place name. Technically, these pieces are either Soumak or brocaded rugs (or sometimes a mixture of both), while stylistically the name usually applies to pieces woven with a design of squares, containing either geometric motifs, or a mixture of geometric and animal motifs, especially long-tailed birds.

Vine leaves - Give a yellow dye (as do autumnal leaves).

Warp - Longitudinal threads forming part of the foundation of a carpet.

Weft - Latitudinal threads forming part of the foundation of a carpet.

Weld - Extract of the Reselda lutuola plant, gives a yellow dye.

Whey - Watery part of milk used in combination with madder to give a particular rose red found on certain Sultanabad carpets.