"Attention" is a

bugle call A bugle call is a short tune, originating as a military signal announcing scheduled and certain non-scheduled events on a military installation, battlefield, or ship. Historically, bugles, drums, and other loud musical instruments were used fo ...

sounded as a warning that troops are about to be called to attention. "Attention" was also used for custom automobile horns in the 1930s and 1940s, and is most recognizable for that reason. \header \paper \score

References

Bugle calls {{music-instrument-stub