The Collaborative International Dictionary of English v.0.48:

Mammon \Mam"mon\ (m[a^]m"m[u^]n), n. [L. mammona, Gr. mammwna^s
   riches, Syr. mam[=o]n[=a]; cf. Heb. matm[=o]n a hiding place,
   subterranean storehouse, treasury, fr. t[=a]man to hide.]
   Riches; wealth; the god of riches; riches, personified.
   [1913 Webster]

         Ye can not serve God and Mammon.         --Matt. vi.
                                                  24.
   [1913 Webster]

WordNet (r) 3.0 (2006):

mammon
    n 1: wealth regarded as an evil influence
    2: (New Testament) a personification of wealth and avarice as an
       evil spirit; "ye cannot serve God and Mammon"

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "mammon":
   affluence, and pence, assets, bottomless purse, bulging purse,
   cash, circulating medium, coinage, coined liberty, cold cash,
   currency, dollars, easy circumstances, embarras de richesses,
   emergency money, filthy lucre, fortune, fractional currency, gold,
   handsome fortune, hard cash, hard currency, high income,
   high tax bracket, independence, legal tender, lucre, luxuriousness,
   managed currency, material wealth, medium of exchange, mintage,
   money, money to burn, moneybags, necessity money, opulence,
   opulency, pelf, possessions, postage currency, postal currency,
   pounds, property, prosperity, prosperousness, riches, richness,
   scrip, shillings, silver, six-figure income, soft currency, specie,
   sterling, substance, the almighty dollar, the wherewith,
   the wherewithal, treasure, upper bracket, wealth, wealthiness



Easton's 1897 Bible Dictionary:

Mammon
   a Chaldee or Syriac word meaning "wealth" or "riches" (Luke
   16:9-11); also, by personification, the god of riches (Matt.
   6:24; Luke 16:9-11).


Hitchcock's Bible Names Dictionary (late 1800's):

Mammon, riches


The Devil's Dictionary (1881-1906):

MAMMON, n.  The god of the world's leading religion.  The chief temple
is in the holy city of New York.

    He swore that all other religions were gammon,
    And wore out his knees in the worship of Mammon.
                                                            Jared Oopf