Main Entry: oys·ter

Pronunciation: \ˈȯis-tər\

Function: noun

Usage: often attributive

Etymology: Middle English oistre, from Anglo-French, from Latin ostrea, from Greek ostreon; akin to Greek ostrakon shell, osteon bone — more at osseous

Date: 13th century

1 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
2 : something that is or can be readily made to serve one's personal ends <the world was her oyster>
3 : a small mass of muscle contained in a concavity of the pelvic bone on each side of the back of a fowl
4 : an extremely taciturn person
5 : a grayish-white color