oyster

noun, oys·ter often attributive \ˈȯis-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

See oyster defined for English-language learners

See oyster defined for kids

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

cloister, hoister, roister

OYSTER Defined for Kids

oyster

noun oys·ter \ˈȯi-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