The Collaborative International Dictionary of English v.0.48:

Grosgrain \Gros"grain`\, a. [F. Cf. Grogram.]
   Of a coarse texture; -- applied to silk with a heavy thread
   running crosswise.
   [1913 Webster]

WordNet (r) 3.0 (2006):

grosgrain
    n 1: a silk or silklike fabric with crosswise ribs