coalitionn.[LL. coalitio: cf. F. coalition. See Coalesce.]1. The act of coalescing; union into a body or mass, as of separate bodies or parts; as, a coalition of atoms.(Bentley.)()2. A combination, for temporary purposes, of persons, parties, or states, having different interests.()A coalition of the puritan and the blackleg. (J. Randolph.)The coalition between the religious and worldly enemies of popery. (Macaulay.)()