It is basically the long strip made up of mostly wooden material that is present on the front of a guitar. You can play the notes and chords on the fretboard. Now, what is a fretboard diagram?

When I was a kid, that was my favourite sound on the guitar ... of the fretboard… the one, the two and the five. I think that’s sort of my signature," he says of the three-note inversions ...

Intervals: The distance between notes on a guitar’s fretboard (it applies to other instruments too). This can be a complex topic to get your plectrum around, involving major and minor notes ...