Etymology: Old English clam(m , clǫm(m , corresponding to Middle High German klam , German klamm cramp, fetter, constriction, pinching, and, with change of gender, Old High German chlamma , Middle High German klamme in same sense. Compare also Middle High German, German klemme , Dutch klemme , klem , apparently from type *klam(m)jôn- . See also clem v.¹These point to an Old Germanic *klam- , *klamm- , or *klamb- , to press or squeeze together. Some compare *klam- with pre-Germanic glom- in Latin glomus . But Sievers inclines to start < klimb- in Old English climban , German klimmen to climb v., originally to cleave, cling, or adhere; thence an adjective *klambo- sticky, with causal verb *klambjan ‘to make to stick, press, compress’. This would provide a common source for the first four nouns spelt clam, and the first three spelt clamp, with the adjectives and verbs belonging to both series.

Etymology: Originally clam-shell : apparently < clam n.¹; the name referring either to the action of the two valves of the shell in shutting like a pair of clams or pincers; or, as some suggest, to ‘the tenacity with which these animals cling to the rocks’. The original application, however, was not to the rock species of the tropics, but to British bivalves which burrow in sand or mud.

Etymology: < clam adj.¹ or clam v.¹; or perhaps a back-formation < clammy adj. (Compare greed)

Etymology: A variant of clamp n.³: compare the similar interchange of clam n.¹, clam n.² with clamp n.¹, clamp n.²

Etymology: Perhaps onomatopoeic; compare clash , clang , slam : it suggests less notion of ringing and more of crash than clang . But compare clamour v.²

Etymology: apparently short for clammer = clamber n., used of a foot-bridge.

Etymology: Origin uncertain; perhaps an extended use of clam n.²

Etymology: This word, clam n.³, clam v.¹, clammy adj., and other derivatives, form a group of which the mutual relations are not quite clear. Although the verb is as yet cited earlier than the adjective, the latter perhaps has etymological priority: it corresponds also to Dutch and Low German klam , in Kilian klam , klamp , ‘moist, clammy, viscous, sticky’, Danish and Swedish klam ‘dampish, wettish’. Not known in the earlier stages of these languages. Compare clam v.¹

Etymology: Related to clam n.¹ It is not certain that sense 2 belongs to the same word: Jamieson thought that as a schoolboy's word, it might originate in the Latin clam, ‘without the knowledge of’, ‘clandestinely’.

Etymology: First found in 14–15th cent., when it interchanged with cleme , Old English clǽman , to smear, anoint, daub, modern dialect cleam . Of the latter, the past tense clǽmde probably gave Middle English clamde (like cladde , ladde , spradde , lafte , etc.), whence was educed a present clam perhaps helped by clam adj.¹ and by clammy adj. The forms clame , claim , which (with cleam ) are still found in northern dialect, are treated under cleam v., see for ulterior derivation.

Etymology: See clam n.⁶, clamour v.²

Etymology: apparently < clam n.¹ in sense of clutch.

Etymology: < clam n.² 1d.