The Collaborative International Dictionary of English v.0.48:

Ruche \Ruche\, n. [F. ruche ruche, beehive, OF. rusche a
   beehive, which was formerly made of the bark of trees; cf. W.
   rhisg, rhisgl, bark, gael. rusg bark, rind.]
   1. A plaited, quilled, or goffered strip of lace, net,
      ribbon, or other material, -- used in place of collars or
      cuffs, and as a trimming for women's dresses and bonnets.
      [Written also rouche.]
      [1913 Webster]

   2. A pile of arched tiles, used to catch and retain oyster
      spawn.
      [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "ruche":
   crease, creasing, crimp, dog-ear, double, doubling, duplicature,
   flection, flexure, flounce, fold, frill, gather, lapel, lappet,
   plica, plication, plicature, ply, ruching, ruffle, tuck