In music, the subdominant's the technical name for the fourth tonal degree of the diatonic scale. It's so called because it's the same distance "below" the tonic as the dominant's above the tonic - in other words, the tonic's the dominant of the subdominant. It's also the note immediately "below" the dominant (External Link). In the C major scale (white keys on a piano, starting on C), the subdominant's the note F; and the subdominant chord uses the notes F, A, and C. In music theory, the subdo… (More on Subdominant)