co·emp·tion \kōˈempshən\noun (-s) Etymology: Latin coemption-, coemptio coemption, coemptio, from coemptus, past participle of coemere to buy up (from co- + emere to buy) + -ion-, -io -ion — more at redeem obsolete: purchase of all supplies of a commodity in the market especially to gain a monopoly • co·emp·tive\(ˈ)kō|emptiv, -ēv\adjective