The Collaborative International Dictionary of English v.0.48:

Vocal \Vo"cal\ (v[=o]"kal), a. [L. vocalis, fr. vox, vocis,
   voice: cf. F. vocal. See Voice, and cf. Vowel.]
   1. Of or pertaining to the voice or speech; having voice;
      endowed with utterance; full of voice, or voices.
      [1913 Webster]

            To hill or valley, fountain, or fresh shade,
            Made vocal by my song.                --Milton.
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   2. Uttered or modulated by the voice; oral; as, vocal melody;
      vocal prayer. "Vocal worship." --Milton.
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   3. Of or pertaining to a vowel or voice sound; also, spoken
      with tone, intonation, and resonance; sonant; sonorous; --
      said of certain articulate sounds.
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   4. (Phon.)
      (a) Consisting of, or characterized by, voice, or tone
          produced in the larynx, which may be modified, either
          by resonance, as in the case of the vowels, or by
          obstructive action, as in certain consonants, such as
          v, l, etc., or by both, as in the nasals m, n, ng;
          sonant; intonated; voiced. See Voice, and Vowel,
          also Guide to Pronunciation, [sect][sect] 199-202.
      (b) Of or pertaining to a vowel; having the character of a
          vowel; vowel.
          [1913 Webster]

   Vocal cords or Vocal chords. n. pl. (Anat.) The two pairs
      of mucous membranes that project into the larynx, and
      which produce the sounds of speech by vibrating under the
      influence of air exhaled from the lungs. See Larynx, and
      the Note under Voice, n., 1.

   Vocal fremitus [L. fremitus a dull roaring or murmuring]
      (Med.), the perceptible vibration of the chest wall,
      produced by the transmission of the sonorous vibrations
      during the act of using the voice.

   Vocal music, music made by the voice, in distinction from
      instrumental music; hence, music or tunes set to words,
      to be performed by the human voice.

   Vocal tube (Anat.), the part of the air passages above the
      inferior ligaments of the larynx, including the passages
      through the nose and mouth.
      [1913 Webster]

WordNet (r) 3.0 (2006):

vocal music
    n 1: music intended to be performed by one or more singers,
         usually with instrumental accompaniment [syn: vocal
         music, vocal]
    2: music that is vocalized (as contrasted with instrumental
       music)