Chords are groups of notes made up of the 1st, 3rd, and 5th notes of a musical scale that create harmony. There are primary chords based on the 1st, 4th, and 5th notes of any scale, and secondary chords based on the other notes that provide color. Chords can be major or minor, and cadences using certain chord progressions end sections of music. Songwriting involves combining chords and melodies that use notes from the underlying scale.