early 15c., situaten, "to place in a particular state or condition, give a site or position to," from Medieval Latin situatus, past participle of situare "to place, locate," from Latin situs "a place, position" (from PIE root *tkei- "to settle, dwell, be home"). Related: Situated; situating.
"placed, located," with reference to surroundings, 1520s, now obsolete (replaced by situated), adjective from Late Latin situatus, past participle of situare "to place, locate" (see situate (v.)).
Proto-Indo-European root meaning "to settle, dwell, be home."
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit kseti "abides, dwells;" Armenian shen "inhabited;" Greek kome, Lithuanian kaimas "village;" Old Church Slavonic semija "domestic servants;" Old English ham "dwelling place, house, abode," German heim "home," Gothic haims "village."
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.