WordNet (r) 3.0 (2006):

bloc
    n 1: a group of countries in special alliance [syn: bloc,
         axis]

Moby Thesaurus II by Grady Ward, 1.0:

38 Moby Thesaurus words for "bloc":
   Bund, Rochdale cooperative, alliance, assemblage, association,
   axis, band, body, coalition, college, combination, combine,
   common market, confederacy, confederation, consumer cooperative,
   cooperative, cooperative society, corps, council, credit union,
   customs union, economic community, faction, federation,
   free trade area, gang, group, grouping, league, machine, mob,
   partnership, party, political machine, ring, society, union