What’s the terminology for changing a major triad into a diminished chord?
C major – C°7 – Gmin7 – C7 etc.
I can’t remember the term!
Music: Practice & Theory Stack Exchange is a question and answer site for musicians, students, and enthusiasts. It only takes a minute to sign up.Sign up to join this community
It's called a common-tone diminished chord. For more on common-tone diminished chords, see Understanding function of diminished chord in Paganini's 4th caprice.
However, in the specific case presented, the chord labeled as Co7 would actually be F#o7, because it's leading to the G chord. That is, the diminished chord is the leading-tone diminished chord for G minor.