The Collaborative International Dictionary of English v.0.48:

Conditional \Con*di"tion*al\, a. [L. conditionalis.]
   1. Containing, implying, or depending on, a condition or
      conditions; not absolute; made or granted on certain
      terms; as, a conditional promise.
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            Every covenant of God with man . . . may justly be
            made (as in fact it is made) with this conditional
            punishment annexed and declared.      --Bp.
                                                  Warburton.
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   2. (Gram. & Logic) Expressing a condition or supposition; as,
      a conditional word, mode, or tense.
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            A conditional proposition is one which asserts the
            dependence of one categorical proposition on
            another.                              --Whately.
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            The words hypothetical and conditional may be . . .
            used synonymously.                    --J. S. Mill.
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The Collaborative International Dictionary of English v.0.48:

Conditional \Con*di"tion*al\, n.
   1. A limitation. [Obs.] --Bacon.
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   2. A conditional word, mode, or proposition.
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            Disjunctives may be turned into conditionals. --L.
                                                  H. Atwater.
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WordNet (r) 3.0 (2006):

conditional
    adj 1: qualified by reservations
    2: imposing or depending on or containing a condition;
       "conditional acceptance of the terms"; "lent conditional
       support"; "the conditional sale will not be complete until
       the full purchase price is paid" [ant: unconditional,
       unconditioned]