a short, sharp blasting sound, similar to that made by a brass musical instrument like a trumpet or a horn;
e.g. She gave three toots of her trumpet to indicate she was ready to play.
(verb)
to make a short, sharp blasting sound, similar to that made by a brass musical instrument such as a trumpet or a horn, or to cause something to make such a sound;
e.g. The trumpets started to toot out the beginning of the song. I heard him toot the horn outside to let us know he was waiting.