[1] : WordNet (r) 2.0

upper crust
     n : the class occupying the highest position in the social
         hierarchy syn: upper class
see also:
upper class 

[2] : Moby Thesaurus II by Grady Ward, 1.0

66 moby thesaurus words for "upper crust":
   ffvs, vanity fair, ancienne noblesse, aristocracy, baronage,
   baronetage, barons, beau monde, beautiful people, best people,
   blue blood, cafe society, carriage trade, chivalry, cream,
   cream of society, drawing room, elect, elite, establishment,
   fashionable society, flower, gentility, gentry, good society,
   haut monde, high life, high society, in-crowd, jet set,
   jeunesse doree, knightage, lords of creation, monde, nobility,
   noblesse, noblesse de robe, old nobility, overlapping, peerage,
   people of fashion, polite society, power elite, power structure,
   quality, right people, royalty, ruling circles, ruling class,
   salon, smart set, social register, societe, society,
   the four hundred, the best, the best people, the brass,
   the classes, top people, upper class, upper classes, upper ten,
   upper ten thousand, uppercut, world of fashion

Crust >> C Words
Crust, definition of term: Crust
crust_pag1.html

Earths Crust >> E Words
Earths Crust, definition of term: Earths Crust
earths+crust_pag1.html