The Bb/D chord is a Bb Major chord, with the D (the 3rd) as the bass note.
The chord is also referred to as Bb over D, or Bb ‘slash’ D, or simply, B flat with a D in the bass.
Technically, the Bb Major chord with the D in the bass is a first inversion B flat Major chord.
Some Bb/C Chord Theory and Info
- The Bb/D chord contains the notes D, Bb and F.
- It is a B flat Major chord with a D in the bass.
- The root note of Bb/D is Bb, the bass note is D.