noun, oys·ter often attributive \ˈis-tər\

: a type of shellfish that has a rough shell with two parts and that is eaten both cooked and raw

Full Definition of OYSTER

a :  any of various marine bivalve mollusks (family Ostreidae) that have a rough irregular shell closed by a single adductor muscle and include commercially important shellfish
b :  any of various mollusks resembling or related to the oysters
:  something that is or can be readily made to serve one's personal ends <the world was her oyster>
:  a small mass of muscle contained in a concavity of the pelvic bone on each side of the back of a fowl
:  an extremely taciturn person
:  a grayish-white color

Origin of OYSTER

Middle English oistre, from Anglo-French, from Latin ostrea, from Greek ostreon; akin to Greek ostrakon shell, osteon bone — more at osseous
First Known Use: 13th century

Rhymes with OYSTER

OYSTERS Defined for Kids


noun oys·ter \ˈi-stər\

Definition of OYSTER for Kids

:  a shellfish that lives on stony bottoms (oyster beds) in shallow seawater, has a rough grayish shell made up of two hinged parts, and is often used for food
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