- oysterAny 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.
- ostraceanAny bivalve of the family Ostreidae; an oyster.
- ostreaceousOf or pertaining to an oyster, or to a shell.
- ostreaphileAn lover or aficionado of oysters as food.