Why was "tantrum" trending last week?
Old English hwistlian, from Proto-Germanic *khwis-, of imitative origin. Used also in Middle English of the hissing of serpents. Related: Whistled; whistling. To whistle for (with small prospect of getting) is probably from nautical whistling for a wind. To whistle "Dixie" is from 1940.
"tubular musical instrument," Old English hwistle (see whistle (v.)). To wet one's whistle "take a drink" (late 14c.) originally may have referred to pipes, or be an allusion to the throat as a sort of pipe. Phrase clean as a whistle is recorded from 1878. Railroad whistle stop (at which trains stop only if the engineer hears a signal from the station) is recorded from 1934.
short flute having a stopped lower end and a flue that directs the player's breath from the mouth hole at the upper end against the edge of a hole cut in the whistle wall, causing the enclosed air to vibrate. Most forms have no finger holes and sound only one pitch. It was made originally from bird bones, and it is considered by many scholars to be the oldest flute type known. It is mainly used for signaling, though it can be heard in folk ensembles and in contemporary music.