The Collaborative International Dictionary of English v.0.48:

Octave \Oc"tave\, n. [F., fr. L. octava an eighth, fr. octavus
   eighth, fr. octo eight. See Eight, and cf. Octavo,
   Utas.]
   1. The eighth day after a church festival, the festival day
      being included; also, the week following a church
      festival. "The octaves of Easter." --Jer. Taylor.
      [1913 Webster]

   2. (Mus.)
      (a) The eighth tone in the scale; the interval between one
          and eight of the scale, or any interval of equal
          length; an interval of five tones and two semitones.
      (b) The whole diatonic scale itself.
          [1913 Webster]

   Note: The ratio of a musical tone to its octave above is 1:2
         as regards the number of vibrations producing the
         tones.
         [1913 Webster]

   3. (Poet.) The first two stanzas of a sonnet, consisting of
      four verses each; a stanza of eight lines.
      [1913 Webster]

            With mournful melody it continued this octave. --Sir
                                                  P. Sidney.
      [1913 Webster]

   Double octave. (Mus.) See under Double.

   Octave flute (Mus.), a small flute, the tones of which
      range an octave higher than those of the German or
      ordinary flute; -- called also piccolo. See Piccolo.
      [1913 Webster]

   4. A small cask of wine, the eighth part of a pipe.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Piccolo \Pic"co*lo\, n. [It., small.]
   1. (Mus.) A small, shrill flute, the pitch of which is an
      octave higher than the ordinary flute; an octave flute.
      [1913 Webster]

   2. (Mus.) A small upright piano.
      [1913 Webster]

   3. (Mus.) An organ stop, with a high, piercing tone.
      [1913 Webster]

WordNet (r) 3.0 (2006):

piccolo
    n 1: a small flute; pitched an octave above the standard flute

Moby Thesaurus II by Grady Ward, 1.0:

105 Moby Thesaurus words for "piccolo":
   English horn, Pandean pipe, aulos, basset horn, basset oboe,
   bassoon, block flute, bombard, bourdon, cello, claribel, clarinet,
   clarion, concert flute, contrabassoon, contrafagotto, cornet,
   cornopean, cromorna, cromorne, cymbel, diapason, double bassoon,
   double reed, dulciana, fife, fipple flute, flageolet, flute,
   flute stop, foundation stop, fourniture, gamba, gedeckt, gemshorn,
   harmonic flute, hautboy, heckelphone, hornpipe, hybrid stop,
   koppel flute, larigot, licorice stick, melodia, mixture, musette,
   mutation stop, nazard, oaten reed, oboe, oboe da caccia, ocarina,
   octave, organ stop, panpipe, penny-whistle, pipe, plein jeu,
   pommer, posaune, principal, quint, quintaten, rank, ranket,
   recorder, reed, reed instrument, reed stop, register, rohr flute,
   sax, saxophone, sesquialtera, shawm, single reed,
   single-reed instrument, sonorophone, spitz flute, stop,
   stopped diapason, stopped flute, string diapason, string stop,
   sweet potato, syrinx, tabor pipe, tenoroon, tierce, tin-whistle,
   tremolo, trombone, trumpet, twelfth, unda maris, vibrato, viola,
   voix celeste, vox angelica, vox humana, whistle, woods, woodwind,
   woodwind choir, woodwind instrument