bivalve

American  

[bahy-valv] / ˈbaɪˌvælv /

noun

1. Also called lamellibranch.  Zoology. any mollusk, as the oyster, clam, scallop, or mussel, of the class Bivalvia, having two shells hinged together, a soft body, and lamellate gills.

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adjective

1. Botany. having two valves, as a seedcase.

2. Zoology. having two shells, usually united by a hinge.

3. having two similar parts hinged together.

bivalve British  

/ ˈbaɪˌvælv /

noun

1. Also: pelecypod.   lamellibranch.  any marine or freshwater mollusc of the class Pelecypoda (formerly Bivalvia or Lamellibranchia ), having a laterally compressed body, a shell consisting of two hinged valves, and gills for respiration. The group includes clams, cockles, oysters, and mussels

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adjective

1. Also: pelecypod.   lamellibranch.  of, relating to, or belonging to the Pelecypoda

2. Also: bivalvate.  biology having or consisting of two valves or similar parts

   a bivalve seed capsule

bivalve Scientific  

/ bī′vălv′ /

1. Any of various mollusks of the class Bivalvia, having a shell consisting of two halves hinged together. Clams, oysters, scallops, and mussels are bivalves. The class Bivalvia is also called Pelecypoda, and was formerly called Lamellibranchia.

2. Compare univalve

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Other Word Forms

• bivalvular adjective

Etymology

Origin of bivalve

First recorded in 1670–80; bi- ¹ + valve

Explanation

A bivalve is a sea creature with two shells, one on top and one underneath, connected by a kind of hinge. Mussels and clams are bivalves; snails and abalone are not. Bivalves are soft on the inside with a very hard, protective shell on the outside. You know you're looking at a bivalve when you see two distinct halves of that shell, which can swing shut like a door when the animal perceives danger. Oysters fall into this category, and so do scallops. Bivalve, literally "two valves," comes from the Latin valva, "section of a folding door."

Example Sentences

A major highlight of the project is the detailed anatomical study of Myonera aleutiana, a carnivorous bivalve.

From Science Daily • Nov. 2, 2025

He put the wee bivalve in a petri dish and asked a colleague to set it aside.

From New York Times • Feb. 6, 2024

The shells belonged to an assortment of tiny seafloor creatures, including small clams; bivalve crustaceans called ostracods; cone-shaped animals known as hyoliths; and stylophorans, oddly shaped precursors to starfish.

From Scientific American • Sep. 28, 2023

You say bivalve and deep water coral reefs grow over the rigs' legs, yet reefs are otherwise hard to come by in the Northern Gulf.

From Salon • Sep. 26, 2023

The pinna has a smooth mouth; but the large oyster has a wide mouth, and is bivalve, and has a smooth shell.

From The Deipnosophists, or Banquet of the Learned of Athen?us by Athen?us