1. (n.) The act of combining or uniting; union separate parties into one organization\; as, a coalition of atoms.

2. (n.) A combination, for temporary purposes, of persons, parties, or states, having different interests.

Anschluss Bund Rochdale cooperative addition affiliation agglomeration aggregation agreement alignment alliance amalgamation anschluss assemblage assimilation association axis band blend blending bloc body cabal cahoots cartel centralization coadunation coalescence colleagueship college collegialism collegiality combination combine combo common market communist front composition comradeship confederacy confederation confraternity congeries conglomeration conjugation conjunction consolidation conspiracy consumer cooperative cooperative cooperative society copartnership copartnery corps council credit union customs union economic community ecumenism embodiment encompassment enosis faction federalization federation fellowship fraternalism fraternity fraternization free trade area freemasonry front fusion gang grass-roots movement ground swell group grouping hookup inclusion incorporation integration junction junta league machine marriage meld melding mergence merger merging mob movement package package deal partnership party political front political machine popular front ring society sodality solidification sorority syncretism syndication syneresis synthesis tie-in tie-up unification union wedding