The Collaborative International Dictionary of English v.0.48:

Piping \Pip"ing\ (p[imac]p"[i^]ng), a. [From Pipe, v.]
   1. Playing on a musical pipe. "Lowing herds and piping
      swains." --Swift.
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   2. Peaceful; favorable to, or characterized by, the music of
      the pipe rather than of the drum and fife. --Shak.
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   3. Emitting a high, shrill sound.
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   4. Simmering; boiling; sizzling; hissing; -- from the sound
      of boiling fluids.
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   Piping crow, Piping crow shrike, Piping roller (Zool.),
      any Australian bird of the genus Gymnorhina, esp.
      Gymnorhina tibicen, which is black and white, and the
      size of a small crow. Called also caruck.

   Piping frog (Zool.), a small American tree frog (Hyla
      Pickeringii) which utters a high, shrill note in early
      spring.

   Piping hot, boiling hot; hissing hot; very hot. [Colloq.]
      --Milton.
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