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

From fried shrimp to fresh oysters, enjoy the best of the coast at these flip-flop-friendly spots. —Kaitlyn Yarborough, Southern Living, 11 Mar. 2025

The café sold items ranging from cioppino to sautéed scallops to oysters on the shell. —Samantha Gowen, Orange County Register, 25 Feb. 2025

For many of our readers, the world has been their oyster these last months. —Jackie Burrell, The Mercury News, 24 Feb. 2025

Consumer Reports recommends not using your garbage disposal on: Oil and grease. Shells from clams and oysters. Artichokes. —Cody Godwin, USA TODAY, 20 Feb. 2025

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