From Longman Dictionary of Contemporary Englishfretboardfret‧board /ˈfretbɔːd $ -bɔːrd/ noun [countable] the long piece of wood on the neck (=straight part) of a guitar against which the fingers press the strings to change the note
Examples from the Corpus
fretboard• The string spacing is far too narrow, not only on the fretboard but more especially with regard to the right hand.• Example 4 is a great lick for covering the whole fretboard from top to bottom.• To understand this concept, think of your fretboard as a conveyor belt.