Definitions

1. adjective

of or relating to a musical interval or chord that is a minor third below the tonic

“The subtonic chord was used in the jazz composition to create a melancholic atmosphere.”

2. noun

a minor third below the tonic

“The subtonic is the interval that completes the minor chord.”

3. noun

the lowest note in the harmonic series of a chord, often used to create tension

“The subtonic note in the chord added a sense of uncertainty to the musical piece.”