Final answer:
In music, particularly in genres such as heavy rock and heavy metal, a type of harmony that only includes the root and fifth note, and lacks major or minor quality, is known as a Power Chord. They have a strong and intense sound.
Step-by-step explanation:
The term that refers to a type of harmony lacking major or minor quality, that includes only the root and fifth is known as a Power Chord.
A power chord is often used in genres such as heavy rock and heavy metal because it has a strong, raw sound that provides power and intensity to the music. Power chords are notated as a note followed by a '5', for example 'E5' would be a power chord based on the note 'E'.
In a power chord, only the root note and its fifth are played, and these can be repeated in various octaves. This makes power chords neither major nor minor, as they don't include the third note of the scale which determines the chord's quality.
Learn more about Power Chords