Clam Up Comes From the Shell Snapping Shut
A clam is a burrowing shellfish with two hinged shells. The idiom follows directly from how it defends itself.
A clam is a burrowing shellfish with two hinged shells. The name comes from the older sense of *clam* meaning a clamp or vice — the shells clamp shut, and *clam up*, meaning to fall silent, follows straight from the image. *Happy as a clam* is the short form of an American phrase, *happy as a clam at high water*, when no one can dig it up. An ocean quahog dredged off Iceland in 2006 was aged at 507 years, making it the oldest individual animal ever recorded.
- A hinged shellfish. *Steamed clams.*
- Clam up — go silent. *He clammed up.*
- Happy as a clam — very content. *Happy as a clam.*
- A clamp (archaic). *A clam.*
- Old English — *clamm*, a bond. *The source.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | clam | A clam. |
| Plural | clams | Clams. |
| Verb | clam | Clammed up. |
| Related | clamp | A clamp. |
| Compound | clambake | A clambake. |
- They dug clams at low tide.Shellfish.
- He clammed up under questioning.Idiom.
- One clam lived 507 years.Fact.
About the oldest animal
- An ocean quahog dredged near Iceland in 2006
- Its age was 507 years, read from growth rings in the shell
- It was born around the year 1499
- Researchers named it Ming, for the dynasty then ruling China
- The species routinely lives beyond two centuries
Old English *clamm*, a bond or fetter, related to *clamp*. The shellfish sense is from the 1500s.
Why does clam up mean to go silent?
From the shells snapping shut. The word originally meant a clamp, and the image transferred to a person refusing to speak.
How old was the oldest clam?
An ocean quahog found near Iceland in 2006 was 507 years old, dated by the growth rings in its shell.