noun Etymology: Spanish, probably diminutive of coca head, alteration of coco bogeyman, coconut 1. a soft whitish limestone formed of broken shells and corals cemented together and used for building 2. a small wedge-shaped clam (Donax variabilis) used for broth or chowder and occurring in the intertidal zone of sandy Atlantic beaches from Delaware to the Gulf of Mexico

Merriam-Webster's Collegiate Dictionary