oyster

noun

oys·​ter ˈȯi-stər 

often attributive

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

Examples of oyster in a Sentence

Recent Examples on the Web

How Monster Depicts the Borden Murders Their first attempt involves serving the couple oysters in May, when the series says the city of Fall River dumps its sewage over the oyster beds, contaminating the shellfish with potentially fatal bacteria. — Chris Spargo, PEOPLE, 18 Sep. 2026

Time your visit with the annual Bowen’s Wharf Seafood Festival to sample lobster rolls, chowder, clams, and oysters as the city’s foliage hits its peak. — Beth Luberecki, USA Today, 10 Sep. 2026

Kick off your meal with a selection from the restaurant's impressive raw bar, which has a rotating offering of about 10 types of oysters daily—as well as the guilt-free indulgence of adding a dollop of caviar to any oyster for just $4. — Condé Nast, Condé Nast Traveler, 9 Sep. 2026

Getty Images The Maine Senate race was closely watched even before personal controversies arose around the Democratic nominee, oyster farmer Graham Platner. — Kaia Hubbard, CBS News, 9 Sep. 2026

Word History

Etymology

Middle English oistre, borrowed from Anglo-French oistre, ostre, going back to Latin ostrea, ostreum "bivalve mollusk, oyster," borrowed from Greek óstreion, óstreon, of uncertain origin

Note: Greek óstreion has traditionally been taken to be a derivative, with a suffix -ei-, of a stem going back to Indo-European *h₃esth₁-r-, from the base *h₃esth₁- "bone." See note at ostracon.

First Known Use

13th century, in the meaning defined at sense 1a

Phrases Containing oyster

• European flat oyster
• European oyster
• Olympia oyster
• oyster bed
• oyster crab
• oyster cracker
• oyster drill
• oyster mushroom
• oyster plant
• seed oyster
• the world is someone's oyster
• vegetable oyster

Rhymes for oyster

• cloister
• moister
• royster

Kids Definition

oyster

noun

oys·​ter ˈȯi-stər 

: any of various marine mollusks that include important edible shellfish and have a rough uneven shell made up of two hinged parts and closed by a single muscle