oyster

n. 1 bivalve mollusc, esp. An edible kind, sometimes producing a pearl. 2 symbol of all one desires (the world is my oyster). 3 oyster white. adj. Oyster-white. [greek ostreon]

n. Any marine bivalve mollusk of the genus Ostrea. They are usually found adhering to rocks or other fixed objects in shallow water along the seacoasts, or in brackish water in the mouth of rivers. The common European oyster (Ostrea edulis), and the American oyster (Ostrea Virginiana), are the most important species.