Pronunciation: (bī'valv"), [key]
Also called lamellibranch. Zool.any mollusk, as the oyster, clam, scallop, or mussel, of the class Bivalvia, having two shells hinged together, a soft body, and lamellate gills.
1. Bot.having two valves, as a seedcase.
2. Zool.having two shells, usually united by a hinge.
3. having two similar parts hinged together.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.