The Collaborative International Dictionary of English v.0.48:

Million \Mil"lion\ (m[i^]l"y[u^]n), n. [F., from LL. millio, fr.
   L. mille a thousand. See Mile.]
   1. The number of ten hundred thousand, or a thousand
      thousand, -- written 1,000,000. See the Note under
      Hundred.
      [1913 Webster]

   2. A very great number; an indefinitely large number.
      [1913 Webster]

            Millions of truths that a man is not concerned to
            know.                                 --Locke.
      [1913 Webster]

   3. The mass of common people; -- with the article the.
      [1913 Webster]

            For the play, I remember, pleased not the million.
                                                  --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

million
    adj 1: (in Roman numerals, M written with a macron over it)
           denoting a quantity consisting of 1,000,000 items or
           units
    n 1: the number that is represented as a one followed by 6 zeros
         [syn: million, 1000000, one thousand thousand, meg]
    2: a very large indefinite number (usually hyperbole); "there
       were millions of flies" [syn: million, billion,
       trillion, zillion, jillion, gazillion]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "million":
   a billion, a crore, a lakh, a million, a myriad, a nonillion,
   a quadrillion, a thousand, a zillion, billion, considerable, crore,
   ever so many, full many, gobs, heap, heaped-up, jillion, loads,
   many, multifarious, multifold, multiple, multitudinal,
   multitudinous, myriad, no few, not a few, numerous, quite some,
   slew, ten million, thousand, very many, wads, zillion