(1) The result of twisting together in one or more operations two or more single, folded, or cabled yarns
(2) A product as defined in (1) intended particularly for sewing purposes. (Known also as sewing thread.)
(3) A component of silk yarn. It is the product of winding together without twist a number of baves. A three-thread silk yarn is the result of folding three such products together
(4) A textile yam in general.
Used as a verb, to pass sliver, yarn, or fabric over, under, or through any element which will control its path.
Textile Resource (http://www.textile.org.uk)
A fine cord of fibrous material spun out to considerable length, especially when composed of two or more plys twisted together.
Textile Links (http://www.textilelinks.com)