Definition of oyster
1a
: 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
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Merriam-Webster unabridged
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Time Traveler for oyster
The first known use of oyster was in the 13th century
See more words from the same century