monopoly (n.) Look up monopoly at Dictionary.com
"exclusive control of a commodity or trade," 1530s, from Latin monopolium, from Greek monopolion "right of exclusive sale," from mono- + polein "to sell," from PIE root *pel- (5) "to sell" (cognates: Sanskrit panate "barters, purchases," Lithuanian pelnas "gain," Old Church Slavonic splenu, Russian polon "prey, booty," Old Norse falr, Dutch veil, German feil "for sale, venal").

Alternative form monopole (1540s, from the Old French form of the word) was common in 16c. The popular board game, invented by Charles Darrow, is from 1935. Monopoly money "unreal currency" is attested from 1972, in reference to the paper used in the game.