The Collaborative International Dictionary of English v.0.48:

Beneficial \Ben`e*fi"cial\, a. [Cf. F. b['e]n['e]ficial, LL.
   beneficialis.]
   1. Conferring benefits; useful; profitable; helpful;
      advantageous; serviceable; contributing to a valuable end;
      -- followed by to.
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            The war which would have been most beneficial to us.
                                                  --Swift.
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   2. (Law) Receiving, or entitled to have or receive,
      advantage, use, or benefit; as, the beneficial owner of an
      estate. --Kent.
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   3. King. [Obs.] "A beneficial foe." --B. Jonson.
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   Syn: See Advantage.
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WordNet (r) 3.0 (2006):

beneficial
    adj 1: promoting or enhancing well-being; "an arms limitation
           agreement beneficial to all countries"; "the beneficial
           effects of a temperate climate"; "the experience was good
           for her" [syn: beneficial, good]