The Collaborative International Dictionary of English v.0.48:

Grogram \Grog"ram\, Grogran \Grog"ran\, n. [OF. gros-grain,
   lit., gros-grain, of a coarse texture. See Gross, and
   Grain a kernel, and cf. Grog.]
   A coarse stuff made of silk and mohair, or of coarse silk.
   [1913 Webster]