Whistle is defined as to make a clear, high and shrill sound.(verb)
An example of whistle is for a bird to sing out a tune.
The definition of a whistle is a clear, high, shrill sound, or a device for making such a sound.(noun)
An example of a whistle is what a referee blows in a soccer game.
See whistle in Webster's New World College Dictionary
Origin: ME whistlen < OE hwistlian: for IE base see whisper
See whistle in American Heritage Dictionary 4
verb whis·tled, whis·tling, whis·tles verb, intransitive
Origin: Middle English whistlen
Origin: , from Old English hwistlian.
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