clam

clam up, Slang. to refuse to talk or reply; refrain from talking or divulging information: The teacher asked who had thrown the eraser, but the class clammed up.

Origin:
1585–95; short for clam-shell, i.e., bivalve with a shell that clamps. See clam², shell

Related forms

clam·like, adjective

clam·mer, noun

Dictionary.com Unabridged

noun

British Dialect, clamp¹ ( defs 1–3 ).

Machinery. (formerly) pincers.

Origin:
before 1000; Middle English; Old English, derivative of clamm fetter, grasp; cognate with German Klamm fetter; akin to clamp

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2013.
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Link To clam

Collins

World English Dictionary

clam¹ (klæm)

—n
1.	any of various burrowing bivalve molluscs of the genera Mya, Venus, etc. Many species, such as the quahog and soft-shell clam, are edible and Tridacna gigas is the largest known bivalve, nearly 1.5 metres long
2.	the edible flesh of such a mollusc
3.	informal a reticent person

—vb , clams, clamming, clammed
4.	chiefly (US) (intr) to gather clams

[C16: from earlier clamshell, that is, shell that clamps; related to Old English clamm fetter, Old High German klamma constriction; see clamp¹]

clam² (klæm)

—vb , clams, clamming, clammed
	a variant of clem

clem or clam (klɛm)

—vb , clems, clemming, clemmed, clams, clamming, clammed
	dialect (English) (when tr, usually passive) to be hungry or cause to be hungry

[C16: of Germanic origin; related to Dutch, German klemmen to pinch, cramp; compare Old English beclemman to shut in]

clam or clam

—vb

[C16: of Germanic origin; related to Dutch, German klemmen to pinch, cramp; compare Old English beclemman to shut in]

Collins English Dictionary - Complete & Unabridged 10th Edition
2009 © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009
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Etymonline

Word Origin & History

clam

c.1500, "bivalve mollusk," originally Scottish, from M.E. clam "pincers, vice, clamp," from O.E. clamm "bond, fetter," from P.Gmc. *klam-. Clambake is from 1835. Clam up is 1916, Amer.Eng., but clam was used in this sense as an interjection c.1350.

Online Etymology Dictionary, © 2010 Douglas Harper
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Slang Dictionary

clam definition

n.
a dollar. (Underworld.) : You got a couple of clams I can bum for a little bottle?
n.
a tight-lipped person. : Suddenly, she became a clam and wouldn't talk anymore.

Dictionary of American Slang and Colloquial Expressions by Richard A. Spears.Fourth Edition.
Copyright 2007. Published by McGraw Hill.
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FOLDOC

Computing Dictionary

CLAM definition

mathematics, tool
A system for symbolic mathematics, especially General Relativity. It was first implemented in ATLAS assembly language and later Lisp.
See also ALAM.
["CLAM Programmer's Manual", Ray d'Inverno & Russell-Clark, King's College London, 1971].
(1994-11-08)

The Free On-line Dictionary of Computing, © Denis Howe 2010 http://foldoc.org
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American Heritage

Idioms & Phrases

clam

In addition to the idiom beginning with clam, also see happy as the day is long (as a clam).