Source : Webster's Revised Unabridged Dictionary (1913)

Whistle \Whis"tle\, v. i. [imp. & p. p. {Whistled}; p. pr. & vb.
   n. {Whistling}.] [AS. hwistlian; akin to Sw. hvissla, Dan.
   hvisle, Icel. hv[=i]sla to whisper, and E. whisper. [root]43.
   See {Whisper}.]
   1. To make a kind of musical sound, or series of sounds, by
      forcing the breath through a small orifice formed by
      contracting the lips; also, to emit a similar sound, or
      series of notes, from the mouth or beak, as birds.

            The weary plowman leaves the task of day, And,
            trudging homeward, whistles on the way. --Gay.

   2. To make a shrill sound with a wind or steam instrument,
      somewhat like that made with the lips; to blow a sharp,
      shrill tone.

   3. To sound shrill, or like a pipe; to make a sharp, shrill
      sound; as, a bullet whistles through the air.

            The wild winds whistle, and the billows roar.
                                                  --Pope.