ruche n.

type of frill, a full plaiting of material used as trimming for women's garments at the neck and wrists, 1827, from French ruche "frill," literally "beehive" (13c.), a word of Celtic origin (compare Breton rusken), from Proto-Celtic *rusca "bark." The notion is the resemblance to the plaiting in straw beehives. Related: Ruched; ruching.