deconcentrate v.

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-.

1630s, "to bring or come to a common center," from concenter (1590s), from Italian concentrare, from assimilated form of Latin com "with, together" (see con-) + centrum "center" (see center (n.)).

Meaning "condense" is from 1680s; that of "intensify the action of" is from 1758. Sense of "mentally focus" is from 1860s, on the notion of "concentrate the mind or mental powers." Related: Concentrated; concentrating.