What is the meaning of Oyster?

Any of certain marine bivalve mollusks, especially those of the family Ostreidae (the true oysters), 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 delicate oyster-shaped morsel of dark meat contained in a small cavity of the bone on each side of the lower part of the back of a fowl.

A pale beige color tinted with grey or pink, like that of an oyster.

A person who keeps secrets.

Something at one's disposal.

A shoplifter.

Ellipsis of Oyster card.

Of a pale beige colour tinted with grey or pink, like that of an oyster.

To fish for oysters.

Source: wiktionary.org