The Collaborative International Dictionary of English v.0.48:

Prelude \Pre*lude"\, v. t.
   1. To introduce with a previous performance; to play or
      perform a prelude to; as, to prelude a concert with a
      lively air.
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   2. To serve as prelude to; to precede as introductory.
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            [Music] preluding some great tragedy. --Longfellow
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The Collaborative International Dictionary of English v.0.48:

Prelude \Pre"lude\, n. [F. pr['e]lude (cf. It. preludio, LL.
   praeludium), fr. L. prae before + ludus play. See Prelude,
   v. t.]
   An introductory performance, preceding and preparing for the
   principal matter; a preliminary part, movement, strain, etc.;
   especially (Mus.), a strain introducing the theme or chief
   subject; a movement introductory to a fugue, yet independent;
   -- with recent composers often synonymous with overture.
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         The last Georgic was a good prelude to the Aenis
                                                  --Addison.
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         The cause is more than the prelude, the effect is more
         than the sequel, of the fact.            --Whewell.
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   Syn: Preface; introduction; preliminary; preamble;
        forerunner; harbinger; precursor.
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The Collaborative International Dictionary of English v.0.48:

Prelude \Pre*lude"\, v. i. [imp. & p. p. Preluded; p. pr. &
   vb. n. Preluding.] [L. praeludere, praelusum; prae before +
   ludere to play: cf. F. pr['e]luder. See Ludicrous.]
   To play an introduction or prelude; to give a prefatory
   performance; to serve as prelude.
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         The musicians preluded on their instruments. --Sir. W.
                                                  Scott.
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         We are preluding too largely, and must come at once to
         the point.                               --Jeffrey.
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WordNet (r) 3.0 (2006):

prelude
    n 1: something that serves as a preceding event or introduces
         what follows; "training is a necessary preliminary to
         employment"; "drinks were the overture to dinner" [syn:
         preliminary, overture, prelude]
    2: music that precedes a fugue or introduces an act in an opera
    v 1: serve as a prelude or opening to
    2: play as a prelude