oyster

American  

[oi-ster] / ˈɔɪ stər /

noun

1. any of several edible, marine, bivalve mollusks of the family Ostreidae, having an irregularly shaped shell, occurring on the bottom or adhering to rocks or other objects in shallow water.

2. the oyster-shaped bit of dark meat in the front hollow of the side bone of a fowl.

3. Slang. a closemouthed or uncommunicative person, especially one who keeps secrets well.

4. something from which a person may extract or derive advantage.

   The world is my oyster.

5. oyster white.

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verb (used without object)

oysters, present (3rd person singular) oystered, past participle, past oystering present participle

1. to dredge for or otherwise take oysters.

oyster British  

/ ˈɔɪstə /

noun

1. 1. any edible marine bivalve mollusc of the genus Ostrea, having a rough irregularly shaped shell and occurring on the sea bed, mostly in coastal waters

   2. ( as modifier )

      oyster farm

      oyster knife

2. any of various similar and related molluscs, such as the pearl oyster and the saddle oyster ( Anomia ephippium )

3. the oyster-shaped piece of dark meat in the hollow of the pelvic bone of a fowl

4. something from which advantage, delight, profit, etc, may be derived

   the world is his oyster

5. informal a very uncommunicative person

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verb

1. (intr) to dredge for, gather, or raise oysters

oyster Idioms  

1. see world is one's oyster.

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Other Word Forms

Conjugated Forms

Present

• have oystered
  perfect
• has oystered
  perfect 3rd person singular
• is oystering
  progressive 3rd person singular
• are oystering
  progressive
• has been oystering
  perfect progressive 3rd person singular
• am oystering
  progressive 1st person singular
• have been oystering
  perfect progressive
• oystering
  participle
• oysters
  singular 3rd person

Past

• had oystered
  perfect
• were oystering
  progressive plural
• was oystering
  progressive singular
• oystered
  simple
• oystered
  participle
• had been oystering
  perfect progressive

Future

• will oyster
  simple
• will have oystered
  perfect
• will be oystering
  progressive
• will have been oystering
  perfect progressive

Etymology

Origin of oyster

1325–75; Middle English oistre < Middle French < Latin ostrea < Greek óstreon; see ostracize

Explanation

An oyster is an animal that lives in the sea, a rough-shelled mollusk. To find a pearl inside an oyster, you first have to find a "pearl oyster" — a rare cousin of the oysters people commonly eat. You can usually tell you've found an oyster on the beach because its shell is bumpy and irregular, unlike the smoother clams or mussels you might see. There are few kinds of oysters that are edible (both cooked and raw), and many others that aren't. You may have heard the expression "the word ls your oyster," which is one of Shakespeare's many linguistic inventions; he means the world is yours to seize, open, and use as you wish.

Example Sentences

A financial disclosure form connected to his Senate campaign lists his mother’s restaurant as the only major customer paying his oyster business.

From The Wall Street Journal • Jun. 6, 2026

Platner, with his war record, oyster farmer's gnarled hands, and plain talk, seemed to fit the bill.

From Barron's • May 3, 2026

Kelp, he says, carries the character of the water it grew in - the same quality that wine people call terroir and oyster people call merroir.

From BBC • Apr. 29, 2026

Trees colonized by golden oyster mushrooms contained far fewer fungal species, and the overall mix of fungi was altered compared to unaffected trees.

From Science Daily • Apr. 24, 2026

There must have been a reason, a really good reason, Daddy was gone, but Mama’s mouth was shut up tighter than an oyster.

From "Root Magic" by Eden Royce

Related Words

• clam
• conch
• crawfish
• crustacean
• lobster
• mollusk
• mussel
• prawn
• scallop
• shrimp
• snail