[n] the act of forming an alliance or confederation [n] a union of political organizations [n] the state of being allied or confederated
alliance, alliance, confederacy, federation
addition, affiliation, agglomeration, aggregation, agreement, alignment, alliance, amalgamation, Anschluss, assemblage, assimilation, association, axis, band, blend, blending, bloc, body, Bund, cabal, cahoots, cartel, centralization, coadunation, coalesce