WordNet (r) 3.0 (2006):

social class
    n 1: people having the same social, economic, or educational
         status; "the working class"; "an emerging professional
         class" [syn: class, stratum, social class, socio-
         economic class]

Moby Thesaurus II by Grady Ward, 1.0:

27 Moby Thesaurus words for "social class":
   ashram, association, body, caste, clan, class, colony,
   commonwealth, commune, community, economic class, endogamous group,
   extended family, family, gens, kinship group, moiety,
   nuclear family, order, phratria, phratry, phyle, settlement,
   social circle, society, subcaste, totem