The Collaborative International Dictionary of English v.0.48:

Contribution \Con`tri*bu"tion\, n. [L. contributio: cf. F.
   contribution.]
   1. The act of contributing.
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   2. That which is contributed; -- either the portion which an
      individual furnishes to the common stock, or the whole
      which is formed by the gifts of individuals.
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            A certain contribution for the poor saints which are
            at jerusalem.                         --Rom. xv. 26.
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            Aristotle's actual contributions to the physical
            sciences.                             --Whewell.
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   3. (Mil.) An irregular and arbitrary imposition or tax leved
      on the people of a town or country.
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            These sums, . . . and the forced contributions paid
            by luckless peasants, enabled him to keep his
            straggling troops together.           --Motley.
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   4. (Law) Payment, by each of several jointly liable, of a
      share in a loss suffered or an amount paid by one of their
      number for the common benefit.
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WordNet (r) 3.0 (2006):

contribution
    n 1: the part played by a person in bringing about a result; "I
         am proud of my contribution in advancing the project";
         "they all did their share of the work" [syn:
         contribution, part, share]
    2: a voluntary gift (as of money or service or ideas) made to
       some worthwhile cause [syn: contribution, donation]
    3: act of giving in common with others for a common purpose
       especially to a charity [syn: contribution, donation]
    4: an amount of money contributed; "he expected his contribution
       to be repaid with interest"
    5: a writing for publication especially one of a collection of
       writings as an article or story