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.-to make a shrill sound with a wind or steam instrument, somewhat like that made with the lips; to blow a sharp, shrill tone.-to sound shrill, or like a pipe; to make a sharp, shrill sound; as, a bullet whistles through the air.-to form, utter, or modulate by whistling; as, to whistle a tune or an air.-to send, signal, or call by a whistle.-a sharp, shrill, more or less musical sound, made by forcing the breath through a small orifice of the lips, or through or instrument which gives a similar sound; the sound used by a sportsman in calling his dogs; the shrill note of a bird; as, the sharp whistle of a boy, or of a boatswain's pipe; the blackbird's mellow whistle.-the shrill sound made by wind passing among trees or through crevices, or that made by bullet, or the like, passing rapidly through the air; the shrill noise (much used as a signal, etc.) made by steam or gas escaping through a small orifice, or impinging against the edge of a metallic bell or cup.-an instrument in which gas or steam forced into a cavity, or against a thin edge, produces a sound more or less like that made by one who whistles through the compressed lips; as, a child's whistle; a boatswain's whistle; a steam whistle (see steam whistle, under steam).-the mouth and throat; -- so called as being the organs of whistling.