If you play the flute or trumpet, you might know that embouchure refers to the way you put your mouth on the instrument in order to make the proper sound. Sometimes the mouthpiece itself is also called an embouchure.
Brass and woodwind instruments are all played by blowing into or across an opening, the embouchure. As a method of playing such instruments, embouchure is a way of holding your mouth-including lips, facial muscles, and teeth. This often involves buzzing your lips against the instrument's mouthpiece. Embouchure is a French word that means "river mouth" (from bouche, "mouth") and it used to actually refer to the mouth of a river.