late 15c., from Old French aloter (Modern French allotir) "to divide by lots, to divide into lots," from à "to" (see ad-) + loter "lot," a word of Germanic origin (cognates: Gothic hlauts, Old High German hloz, Old English hlot; see lot). Related: Allotted; allotting.
[allot etymology, allot origin, 英语词源]