Is a distance of two frets on the guitar or the distance of two semitones. Examples of tones could be: A – B, G – A, E – F#, B – C#, Eb to F etc. Note that the distances between E and F and B and C are only a semitone. These distance relationships of tones and semitones apply to all instruments. Observe the logic on the piano keyboard with the spacing between B and C and E and F where there is no black key between those notes.