Old English pipian "to play on a pipe," from Latin pipare "to peep, chirp" (see pipe (n.1)). Compare Dutch pijpen, German pfeifen. Meaning "convey through pipes" is first recorded 1887. Related: Piped; piping. Piping hot is in Chaucer, a reference to hissing of food in a frying pan; to pipe up (early 15c.) originally meant "to begin to play" (on a musical instrument); sense of "to speak out" is from 1856. Pipe down "be quiet" is from 1900, probably a reversal of this, but earlier (and concurrently) in nautical jargon it was a bo'sun's whistle signal to dismiss the men from duty (1833).[pipe etymology, pipe origin, 英语词源]