a combination or alliance, esp. a temporary one between persons, factions, states, etc.
2.
a union into one body or mass; fusion.
Origin: 1605–15; < L coalitiōn- (s. of coalitiō), equiv. to coalit(us), ptp. of coalēscere (co-co-+ ali-, ptp. s. of alere to nourish + -tus ptp. suffix) + -iōn--ion; see coalesce
[koh-uh-lish-uh
n] 