Major Thirds 1 2 3 Major Thirds A Major Third is the distance between the first and third notes in the major scale. A Major 3rd is also equivalent to 2 Whole Steps, or 4 semitones. July 30, 2011 1 2 3 Major Thirds A Major Third is the distance between the first and third notes in the major scale. A Major 3rd is also equivalent to 2 Whole Steps, or 4 semitones. You’re Finished! Click one of the links below to take a lesson Piano Guitar Bass