A standard acoustic guitar has two parts in its structure:
Neck: It is the topmost part in the guitar structure which consists of further two parts :
Headstock is the part from were all the tuning is done. It consists of machineheads and nut .
Machineheads are the tuning screws which are rotatable part in the guitar. Below is the picture of machineheads for your reference:
Nut is the part which holds up the strings in a guitar.
Freatboard is the part which consist on frets and from where all the chords and scales are played in a guitar.