<p><strong>Noun</strong></p><ul><li>Also called lamellibranch.</li><li>any mollusk, as the oyster, clam, scallop, or mussel, of the class Bivalvia, having two shells hinged together, a soft body, and lamellate gills.</li></ul><p><strong>Adjective</strong></p><ul><li>Botany. having two valves, as a seedcase.</li><li>Zoology. having two shells, usually united by a hinge.</li><li>having two similar parts hinged together.</li></ul>