"to form in a coagulated mass," early 15c., from clot (n.). Of fluids (especially blood) from 1590s. Related: Clotted; clotting. Clotted cream (1799) originally was clouted cream (1540s).
1967, American English, from Yiddish klots "clumsy person, blockhead," literally "block, lump," from Middle High German klotz "lump, ball." Compare German klotz "boor, clod," literally "wooden block" (see clot (n.)).
Old English clyster "a number of things growing naturally together," probably from the same root as clot (n.). Meaning "a number of persons, animals, or things gathered in a close body" is from c. 1400. Of stars, from 1727. Cluster-bomb attested by 1950.
1550s, "to collect in heaps, crowd together in disorder," variant of clotern "to form clots, to heap on" (c. 1400); related to clot (n.), and perhaps influenced by cluster. Sense of "to litter, to crowd (a place) by a disorderly mass of things" is first recorded 1660s. Related: Cluttered; cluttering.
Old English clut "lump of something," also "patch of cloth put over a hole to mend it," from Proto-Germanic *klutaz (source also of Old Norse klute "kerchief," Danish klud "rag, tatter," Frisian klut "lump," Dutch kluit "clod, lump"); perhaps related to clot (v.).
In later use "a handkerchief," also "a woman's sanitary napkin." Sense of "a blow" is from early 14c., from the verb. Slang sense of "personal influence" (especially in politics) is by 1946, American English, on the notion of "punch, force."
"lump of earth or clay," Old English clod- (in clodhamer "the fieldfare," a kind of thrush), from Proto-Germanic *kludda-, from PIE *gleu- (see clay).
Synonymous with collateral clot until the meanings differentiated 18c. Meaning "person" ("mere lump of earth") is from 1590s; that of "blockhead, dolt, stupid fellow" is from c. 1600 (compare clodpate, clodpoll, etc. in the same sense). It also was a verb in Middle English, meaning both "to coagulate, form into clods" and "to break up clods after plowing."
before vowels thromb-, word-forming element meaning "blood clot," from combining form of Greek thrombos "clot of blood" (see thrombus).
1690s, Modern Latin, from Greek thrombos "lump, piece, clot of blood, curd of milk," a word of uncertain etymology.
early 15c., "to clot, congeal, become curdled, change from a liquid into a thickened mass; to make to clot," from Latin coagulatus, past participle of coagulare "to cause to curdle," from cogere "to curdle, collect" (see cogent). The earlier verb was coagule, c. 1400, from Old French coaguler and directly from Latin. Related: Coagulated; coagulating.