n. An edible bivalve mollusk of the family Ostreidæ, such as Ostrea edulis, the common species of Europe, and O. virginica, that of the Atlantic coast of the United States.n. One of many other bivalves of the same order, but of a different family. Thus, the pearl-oyster belongs to the Aviculidæ.n. The oyster-shaped bit of dark meat in the front hollow of the side-bone of a turkey or similar bird.n. Figuratively, some profit or advantage which one may seize and hold.n. Among packers, steamed oysters packed in hermetically sealed cans: a trade-name.To engage in oyster-fishing; take oysters in any way.