Interval
Distance between two notes, measured in tones and semitones.
An interval is the distance between two notes, measured in tones and semitones. On guitar, each fret equals one semitone. Intervals give chords their identity: a major chord contains a major third (4 semitones) and a perfect fifth (7 semitones); a minor chord has a minor third (3 semitones). Recognising intervals by ear is the foundation of relative pitch.