The Collaborative International Dictionary of English v.0.48:

Inflection \In*flec"tion\, n. [L. inflexio : cf. F. inflexion.
   See Inflect.] [Written also inflecxion.]
   1. The act of inflecting, or the state of being inflected.
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   2. A bend; a fold; a curve; a turn; a twist.
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   3. A slide, modulation, or accent of the voice; as, the
      rising and the falling inflection.
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   4. (Gram.) The variation or change which words undergo to
      mark case, gender, number, comparison, tense, person,
      mood, voice, etc.
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   5. (Mus.)
      (a) Any change or modification in the pitch or tone of the
          voice.
      (b) A departure from the monotone, or reciting note, in
          chanting.
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   6. (Opt.) Same as Diffraction.
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   Point of inflection (Geom.), the point on opposite sides of
      which a curve bends in contrary ways.
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WordNet (r) 3.0 (2006):

inflection
    n 1: a change in the form of a word (usually by adding a suffix)
         to indicate a change in its grammatical function [syn:
         inflection, inflexion]
    2: the patterns of stress and intonation in a language [syn:
       prosody, inflection]
    3: deviation from a straight or normal course [syn:
       inflection, flection, flexion]
    4: a manner of speaking in which the loudness or pitch or tone
       of the voice is modified [syn: modulation, inflection]