Oyster

Oyster is the common name for a number of different families of salt water bivalve molluscs that live in marine or brackish habitats, with valves that in some species are highly calcified and often somewhat irregular in shape; many, though not all, oysters belong to the superfamily Ostreoidea. Some species of oyster are commonly eaten and regarded as a delicacy in some places, some pearl oysters are harvested for the pearls that form within their mantle, and others, such as the translucent windowpane oyster, are harvested for their shells.