The Collaborative International Dictionary of English v.0.48:

Opulence \Op"u*lence\, n. [L. opulentia: cf. F. opulence. See
   Opulent.]
   Wealth; riches; affluence. --Swift
   [1913 Webster]

WordNet (r) 3.0 (2006):

opulence
    n 1: wealth as evidenced by sumptuous living [syn: luxury,
         luxuriousness, opulence, sumptuousness]

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "opulence":
   abundance, affluence, ample sufficiency, ampleness, amplitude,
   assets, avalanche, bonanza, bottomless purse, bountifulness,
   bountiousness, bulging purse, bumper crop, copiousness,
   easy circumstances, embarras de richesses, extravagance,
   exuberance, fertility, flood, flow, foison, fortune, full measure,
   fullness, generosity, generousness, gold, great abundance,
   great plenty, gush, handsome fortune, high income,
   high tax bracket, independence, landslide, lavishness, liberality,
   liberalness, lots, lucre, luxuriance, luxuriousness, mammon,
   material wealth, maximum, money, money to burn, moneybags,
   more than enough, much, myriad, myriads, numerousness, opulency,
   outpouring, overflow, pelf, plenitude, plenteousness,
   plentifulness, plenty, possessions, prevalence, prodigality,
   productiveness, profuseness, profusion, property, prosperity,
   prosperousness, quantities, repleteness, repletion, rich harvest,
   rich vein, riches, richness, riot, riotousness, scads, shower,
   six-figure income, spate, stream, substance, substantiality,
   substantialness, superabundance, teemingness, treasure,
   upper bracket, wealth, wealthiness