Univalve
Univalve , noun
[Uni- + valve: compare French univalve.]
(Zoology) 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.
Univalve , adjective
[Compare French univalve.]
(Botany & Zoology) Having one valve; as, a univalve shell or pericarp.
Also: Univalved