Figure Whistle, 7th century - Public domain museum image. A gold figurine of a monkey holding a baseball bat

The whistle is a musical instrument that produces sound by blowing air through a small opening. It has been used for various purposes throughout history, including signaling, communication, and music. Whistles have been found in archaeological sites dating back to ancient civilizations such as the Greeks and Romans. They were used by soldiers as a means of communication during battles, and by shepherds to control their flocks.