"to set aside for a special purpose," 1630s, from Medieval Latin allocate (the common first word of writs authorizing payment), imperative plural of allocare "allocate, allot," from Latin ad "to" (see ad-) + locare "to place," from locus "a place" (see locus). It is a twin of allow. Related: Allocated; allocating. English allocate as an adjective is attested from mid-15c. in legal use.

also re-allocate, "apportion or assign again," by 1868, from re- "back, again" + allocate. Related: Reallocated; reallocating.

early 14c., allouen, "to commend, praise; approve of, be pleased with; appreciate the value of;" also, "take into account or give credit for," also, in law and philosophy, "recognize, admit as valid" (a privilege, an excuse, a statement, etc.). From late 14c. as "sanction or permit; condone;" in business, of expenses, etc., by early 15c.

The Middle English word is from Anglo-French alouer, Old French aloer, alloiier (13c.) "to place, situate, arrange; allot, apportion, bestow, assign," from Latin allocare "allocate" (see allocate). This word in Old French was confused and ultimately merged with aloer; alloer "to praise, commend, approve," from Latin allaudare, adlaudare, a compound of ad "to" (see ad-) + laudare "to praise" (see laud).

Between the two primary significations there naturally arose a variety of uses blending them in the general idea of assign with approval, grant, concede a thing claimed or urged, admit a thing offered, permit, etc., etc. [OED].

From the first word came the sense preserved in allowance "money granted;" from the second came allowance "permission based on approval." The 19c. U.S. colloquial meaning "assert, say," also was in English dialect and goes back to 1570s. Related: Allowed; allowing.

mid-15c., allocacion, "authorization," from Medieval Latin allocationem (nominative allocatio), noun of action from past-participle stem of allocare "allocate, allot," from assimilated form of Latin ad "to" (see ad-) + locare "to place," from locus "a place" (see locus).

early 15c., "to give a part of (one's possessions);" late 15c., "to share, take part in," from Old French empartir, impartir "assign, allot, allocate, share out" (14c.), from Late Latin impartire (also impertire) "to share in, divide with another; communicate," from assimilated form of in- "into, in" (from PIE root *en "in") + partire "to divide, part" (from pars "a part, piece, a share," from PIE root *pere- (2) "to grant, allot").

Meaning "communicate as knowledge or information" is from 1540s; the word was not originally restricted to immaterial things but now usually is only in reference to qualities. Related: Imparted; imparting; impartment.