pholas
noun
pho·las
ˈfōləs
1
capitalized : a large genus of bivalve usually marine mollusks (family Pholadidae) with an elongate-oval rough shell having no hinge ligament, gaping at the end, and having two accessory valves to protect the dorsal margin that with the foot serves as a rasp to bore in wood and stone
2
plural pholades
-ləˌdēz
: any mollusk of the genus Pholas or of the family Pholadidae : piddock 
Word History
Etymology
New Latin, from Greek phōlas stone-boring mollusk, literally, lying in a hole; akin to Greek phylē tribe, clan