Hermit crab Meaning, Definition & Usage

  1. noun small soft-bodied marine crustaceans living in cast-off shells of gastropods

WordNet

Definitions
  1. (Zoöl.), a marine decapod crustacean of the family Paguridæ. The species are numerous, and belong to many genera. Called also soldier crab. The hermit crabs usually occupy the dead shells of various univalve mollusks. See Illust. of Commensal.

Webster 1913