The contemporary word, guitar, was adopted into English from Spanish guitarra, derived from the Latin discussion cithara, which in turn was derived from the earlier Greek conversation kithara, which perhaps derives Fender Telecaster from Persian sihtar. Sihtar itself is related to the Indian instrument, the sitar.
Illustration from a Carolingian Psalter from the 9th century, showing a guitar-like plucked instrument.
Illustration from a Carolingian Psalter from the 9th century, showing a guitar-like plucked instrument.

The nut is a small strip of bone, plastic, brass, corian, graphite, stainless steel, or other medium-hard material, at the joint where the headstock meets the fretboard. Its grooves cicerone the strings onto the fretboard, giving consistent lateral string placement. It is uncommon of the endpoints of the strings' vibrating length. It must be accurately cut, or it can contribute to tuning problems due to string slippage, and/or string buzz.