ruche

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A gathered ruffle or pleat of fabric used for trimming or decorating women's garments.
• intransitive verb To gather fabric in a repeating pattern to make such a pleat or ruffle.
• intransitive verb To gather (fabric) in a repeating pattern to make such a pleat or ruffle.

from The Century Dictionary.

• noun A full quilling, frilling, or plaiting of ribbon, muslin, grenadine, net, lace, or other material, used as a trimming for women's garments, or worn at the neck and wrists.
• noun A loose pile of arched tiles to catch and lodge oyster-spawn.
• noun In zoology, a reticulated folding of the skin found in the hemipenes of some snakes.

from the GNU version of the Collaborative International Dictionary of English.

• noun 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.
• noun A pile of arched tiles, used to catch and retain oyster spawn.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A strip of fabric used for trimming.
• noun A pile of arched tiles, used to catch and retain oyster spawn.