The Collaborative International Dictionary of English v.0.48:

Repetition \Rep`e*ti"tion\ (r[e^]p`[-e]-t[i^]sh"[u^]n), n. [L.
   repetitio: cf. F. r['e]p['e]tition. See Repeat.]
   1. The act of repeating; a doing or saying again; iteration.
      [1913 Webster]

            I need not be barren of accusations; he hath faults,
            with surplus to tire in repetition.   --Shak.
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   2. Recital from memory; rehearsal.
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   3. (Mus.) The act of repeating, singing, or playing, the same
      piece or part a second time; reiteration of a note.
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   4. (Rhet.) Reiteration, or repeating the same word, or the
      same sense in different words, for the purpose of making a
      deeper impression on the audience.
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   5. (Astron. & Surv.) The measurement of an angle by
      successive observations with a repeating instrument.
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   Syn: Iteration; rehearsal. See Tautology.
        [1913 Webster] Repetitional

WordNet (r) 3.0 (2006):

repetition
    n 1: an event that repeats; "the events today were a repeat of
         yesterday's" [syn: repeat, repetition]
    2: the act of doing or performing again [syn: repetition,
       repeating]
    3: the repeated use of the same word or word pattern as a
       rhetorical device