U″ni‐valve (?), n. [Uni- + valve: cf. F. univalve.] (Zoöl.) A shell consisting of one valve only; a mollusk whose shell is composed of a single piece, as the snails and conchs.
☞ Most univalves are spiral and are the shells of gastropods, but many belong to cephalopods and pteropods. A large number of univalves belonging to the gastropods are conical, cup-shaped, or shieldlike, as the limpets.