👉 In the context of music, a "folie" is a musical instrument. It can be a cello, a violin, or any other stringed instrument that has a single string attached to a wooden frame and is tuned to play notes on a different string. This type of instrument is often used in orchestras for soloists or for ensemble music. In addition to being an instrument, a folie is also a term used to refer to the act of playing this specific musical instrument. For