enclosen, "to surround (a plot of ground, a town, a building, etc.) with walls, fences, or other barriers," early 14c., from en- (1) + close (v.), and partially from Old French enclos, past participle of enclore "surround; confine; contain." Specific sense of "to fence in waste or common ground" for the purpose of cultivation or to give it to private owners is from c. 1500. Meaning "place a document with a letter for transmission" is from 1707. Related: Enclosed; enclosing.
also *kleu-, klēu-, Proto-Indo-European root meaning "hook, crook," also "crooked or forked branch" (used as a bar or bolt in primitive structures).
It forms all or part of: anschluss; autoclave; clause; claustrophobia; claves; clavichord; clavicle; clavier; claviger; clechy; clef; cloison; cloisonne; cloister; close (v.); close (adj.); closet; closure; cloture; clove (n.1) "dried flowerbud of a certain tropical tree, used as a spice;" cloy; conclave; conclude; disclose; enclave; enclose; exclude; foreclose; include; occlude; preclude; recluse; seclude; slot (n.2) "bar or bolt used to fasten a door, window, etc."
It is the hypothetical source of/evidence for its existence is provided by: Greek kleis "bar, bolt, key; collarbone," klobos "cage;" Latin clavis "key," clavus "nail," claudere "to shut, close;" Lithuanian kliūti "to catch, be caught on," kliaudžiu, kliausti "to check, hinder," kliūvu, kliūti "to clasp, hang;" Old Church Slavonic ključi "hook, key," ključiti "shut;" Old Irish clo "nail," Middle Irish clithar "hedge, fence;" Old High German sliozan "shut," German schließen "to shut," Schlüssel "key."
1510s, "to enclose with a fence;" c. 1600 as "to enclose or fortify with an embankment;" see mound (n.). From 1859 as "to heap up." Related: Mounded; mounding.
c. 1300, "to enclose with or as if with a curtain," from Old French cortiner, from cortine (see curtain (n.)). Related: Curtained.