| any of numerous crabs, esp. of the genera Pagurus and Eupagurus, that protect their soft uncovered abdomen by occupying the castoff shell of a univalve mollusk. |
| hermit crab n. Any of various crabs belonging to a group within the order Decapoda that protect their soft unarmored abdomens by occupying and carrying about the empty shells of snails or other univalve mollusks. |