decomposition n.

active word-forming element in English and in many verbs inherited from French and Latin, from Latin de "down, down from, from, off; concerning" (see de), also used as a prefix in Latin, usually meaning "down, off, away, from among, down from," but also "down to the bottom, totally" hence "completely" (intensive or completive), which is its sense in many English words.

As a Latin prefix it also had the function of undoing or reversing a verb's action, and hence it came to be used as a pure privative — "not, do the opposite of, undo" — which is its primary function as a living prefix in English, as in defrost (1895), defuse (1943), de-escalate (1964), etc. In some cases, a reduced form of dis-.

late 14c., composicioun, "action of combining," also "manner in which a thing is composed," from Old French composicion (13c., Modern French composition) "composition, make-up, literary work, agreement, settlement," and directly from Latin compositionem (nominative compositio) "a putting together, connecting, arranging," noun of action from past participle stem of componere "to put together, to collect a whole from several parts," from com "with, together" (see com-) + ponere "to place" (past participle positus; see position (n.)).

Meaning "art of constructing sentences" is from 1550s; that of "literary production, that which results from composing" (often also "writing exercise for students") is from c. 1600. Meaning "orderly disposition" is from 1590s. Printing sense "the setting of type" is from 1832; meaning "arrangement of parts in a picture" is from 1706.

1650s, "compounded a second time, compounded from things already composite," from Late Latin compositus, in grammar (rendering Greek parasynthetos), "formed from a compound," literally "placed together," past participle of componere  "to put together, to collect a whole from several parts," from com "with, together" (see com-) + ponere "to place" (past participle positus; see position (n.)). Earlier in English as a noun, "something compounded of composite things" (1620s). Middle English had decompound (adj.) in grammar (mid-15c.).