BIVALVE
bivalve, bivalved
(adjective) used of mollusks having two shells (as clams etc.)
bivalve, pelecypod, lamellibranch
(noun) marine or freshwater mollusks having a soft body with platelike gills enclosed within two shells hinged together
Source: WordNet® 3.1
Etymology
Noun
bivalve (plural bivalves)
Any mollusc belonging to the taxonomic class Bivalvia, characterized by a shell consisting of two hinged sections, such as a scallop, clam, mussel or oyster.
(botany) A pericarp in which the seed case opens or splits into two parts or valves.
Coordinate terms
• univalve
Source: Wiktionary
Bi"valve, n. Etym: [F. bivalve; bi- (L. bis) + valve valve.]
1. (Zoöl.)
Definition: A mollusk having a shell consisting of two lateral plates or
valves joined together by an elastic ligament at the hinge, which is
usually strengthened by prominences called teeth. The shell is closed
by the contraction of two transverse muscles attached to the inner
surface, as in the clam, -- or by one, as in the oyster. See
Mollusca.
2. (Bot.)
Definition: A pericarp in which the seed case opens or splits into two
parts or valves.
Bi"valve, a. Etym: [Pref. bi- + valve.] (Zoöl. & Bot.)
Definition: Having two shells or valves which open and shut, as the oyster
and certain seed vessels.
Source: Webster’s Unabridged Dictionary 1913 Edition