Pipe Down

Pipe Down: To shut-up or be quiet.

On sailing ships signals were given to the crew by sounding the boatswain's (bo'sun's) pipe. One such was 'piping down the hammocks' which was the signal to go below decks and retire for the night. When an officer wanted a sailor to be dismissed below he would have him 'piped down'. There's no unequivocal link between this naval practice and the 'be quiet' meaning. It could well have derived from the fact that, if there was a disturbance onboard ship, officers could quell it by sending the crew below decks, that is, by piping them down.



Ex: Oh pipe down! You don’t even know what you are talking about



Spanish: bajar la voz

German: Halt (mal) die Luft an!