Frill, n. [See Frill, v. i.]. (Zoöl.) (a) A ruffing of a bird's feathers from cold. (b) A ruffle, consisting of a fold of membrane, of hairs, or of feathers, around the neck of an animal. See Frilled lizard (below). (c) A similar ruffle around the legs or other appendages of animals. (d) A ruffled varex or fold on certain shells.
2. A border or edging secured at one edge and left free at the other, usually fluted or crimped like a very narrow flounce.