The guitar has three main parts – head, neck and body.

Head

The head has the tuning keys attached which are used to tune the guitar. When you turn the tuning keys the strings tighten (string tone gets higher) or loosen (string tone gets lower). 

Neck

The top of the neck is called the fingerboard. The fingerboard houses several metal strips called frets and you play between the frets.

Body

The body is the largest part and can be solid wood, hollow, or semi hollow.
This photo is of a solid body and these are also called electric guitars since they require an amplifier to produce any sound.
If the body is hollow they are call acoustic guitars and do not require an amp for sound.

Electronic Guitar Parts

The electronics of an electric guitar is:

Pickups – the pickups send the string vibrations to amp where they are converted to sound.
Volume Knobs – Adjust to loudness of the guitar, some guitars like this one have two volume knobs and some only have one.
Tone Knobs – The tone knob adjust the treble to bass sound of the pickups.
Pickup Switch or Selector: The pickup selector switches between the pickups. The pickup closes to the neck is call the neck pickup and has a low tone, the pickup closes to the bridge is called the bridge pickup and has a high tone. You can select which pickup you want to you can get a variety sounds out of the guitar.

Other Features

Nut – the nut is the first place the strings travel over and they continue down to the bridge.
Bridge – the strings pass over the bridge to the tailpiece.
Tailpiece – The tailpiece is the first place you start when you re-string a guitar its job is to hold a small ball that is attached to the strings. Sometime the bridge and tailpiece are the same piece.

The distance between the nut and the bridge is called the scale length. The scale length of a guitar determines how tight the strings are strung, how large the fret spacing is between frets, and how much sustain a guitar will have. Les Paul guitars are 24  ¾” in scale length while Fender Stratocasters are 25” in scale length.