What is "pholas"

Pholas \Pho"las\, n.; pl. Pholades. [NL., fr. Gr. ?, ?, a kind of mollusk.] (Zo["o]l.) Any one of numerous species of marine bivalve mollusks of the genus Pholas, or family Pholadid[ae]. They bore holes for themselves in clay, peat, and soft rocks.

n. Any of several borrowing marine bivalve molluscs of the genus ''Pholas''.

Pholas is a taxonomic genus of marine bivalve molluscs in the family Pholadidae. Like other members of this family, they have an ability to bore through clay, earth, wood and soft rock.