UNIVALVE
univalve
(adjective) used of mollusks, especially gastropods, as snails etc.
gastropod, univalve
(noun) a class of mollusks typically having a one-piece coiled shell and flattened muscular foot with a head bearing stalked eyes
Source: WordNet® 3.1
Etymology
Adjective
univalve (not comparable)
having one valve; typically used to refer to mollusks, notably slugs and snails.
consisting of a single valve or piece, used to refer to a shell.
Noun
univalve (plural univalves)
A univalve mollusk or its shell.
Usage notes
The term univalve is now considered outdated in scientific classification, and the term gastropod is preferred.
Synonyms
• gastropod
Coordinate terms
• bivalve
Source: Wiktionary
U"ni*valve, n. Etym: [Uni- + valve: cf. F. univalve.] (Zoöl.)
Definition: A shell consisting of one valve only; a mollusk whose shell is
composed of a single piece, as the snails and conchs.
Note: 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.
U"ni*valve, U"ni*valved, a. Etym: [Cf. F. univalve.] (Bot. & Zoöl.)
Definition: Having one valve; as, a univalve shell or pericarp.
Source: Webster’s Unabridged Dictionary 1913 Edition