Definition of lamellibranch
: any of a class (Lamellibranchia) of bivalve mollusks (as clams, oysters, and mussels) that have the body bilaterally symmetrical, compressed, and enclosed within the mantle and that build up a shell whose right and left parts are connected by a hinge over the animal's back
Origin and Etymology of lamellibranch
New Latin Lamellibranchia, from lamella + Latin branchia gill
First Known Use: 1855
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