parts of the guitar: nut

Nut image, gifThe nut is a small strip of ivory, bone, plastic, brass, graphite, or other medium-hard material that braces the strings at the joint where the headstock meets the fretboard.

It is grooved to hold the strings in place, and it is one of the endpoints of the strings' tension. The material used also affects the sound of the guitar. Confusingly, the nut is also sometimes called a bridge; following this terminology, a guitar has two bridges.