From Wikipedia:

Corduroy is a textile composed of twisted fibers that, when woven, lie parallel (similar to twill) to one another to form the cloth’s distinct pattern, a “cord.” Modern corduroy is most commonly composed of tufted cords, sometimes exhibiting a channel (bare to the base fabric) between the tufts. The word “corduroy” can be used as a noun, a transitive verb, or an adjective. Corduroy is, in essence, a ridged form of velvet.