The Collaborative International Dictionary of English v.0.48:

Intonation \In`to*na"tion\, n. [See 1st Intonate.]
   A thundering; thunder. [Obs.] --Bailey.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Intonation \In`to*na"tion\, n. [Cf. F. intonation. See
   Intone.]
   1. (Mus.)
      (a) The act of sounding the tones of the musical scale.
      (b) Singing or playing in good tune or otherwise; as, her
          intonation was false.
      (c) Reciting in a musical prolonged tone; intonating, or
          singing of the opening phrase of a plain-chant, psalm,
          or canticle by a single voice, as of a priest. See
          Intone, v. t.
          [1913 Webster]

   2. The manner of speaking, especially the placement of
      emphasis, the cadence, and the rise and fall of the pitch
      of the voice while speaking.
      [PJC]

WordNet (r) 3.0 (2006):

intonation
    n 1: rise and fall of the voice pitch [syn: intonation,
         modulation, pitch contour]
    2: singing by a soloist of the opening piece of plainsong
    3: the act of singing in a monotonous tone [syn: intonation,
       chanting]
    4: the production of musical tones (by voice or instrument);
       especially the exactitude of the pitch relations

Moby Thesaurus II by Grady Ward, 1.0:

93 Moby Thesaurus words for "intonation":
   AF, accent, accentuation, adaptation, arrangement, articulation,
   audio frequency, bel canto, bravura, cantando, choral singing,
   coloratura, croon, crooning, delivery, demilegato, emphasis,
   execution, expression, fingering, folk singing, frequency,
   fundamental, fundamental tone, glissando, grammatical accent,
   harmonic, harmonization, hum, humming, ictus, inflection,
   instrumentation, intonation pattern, legato, lyricism,
   mezzo staccato, modulation, monotone, monotony, music-making,
   operatic singing, orchestration, overtone, parlando, partial,
   partial tone, performance, phrasing, pianism, pitch, pitch accent,
   pizzicato, preparation, pronunciation, rendering, rendition,
   repercussion, resolution, rhetorical accent, rhythmical accent,
   rubato, scat, scat singing, setting, singing, slur, sol-fa,
   sol-fa exercise, solfeggio, solmization, solution, song,
   speech tune, spiccato, staccato, stress accent, stress arsis,
   suprasegmental, suspension, thesis, tone, tone accent,
   tone painting, tonelessness, tonic sol-fa, touch, transcription,
   vocal music, vocalization, warbling, yodel, yodeling