Definition of whistle :
1. 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.
2. 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).
3. The mouth and throat; - so called as being the organs of whistling.
4. To form, utter, or modulate by whistling; as, to whistle a tune or an air.
5. 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.
6. To make a shrill sound with a wind or steam instrument, somewhat like that made with the lips; to blow a sharp, shrill tone.
7. To send, signal, or call by a whistle.
8. To sound shrill, or like a pipe; to make a sharp, shrill sound; as, a bullet whistles through the air.
scream (part of speech: verb)
alarm (part of speech: noun)
shrillness (part of speech: noun)
sibilate (part of speech: verb)
sibilation (part of speech: noun)