i wanted to ask something related to the 5 types of seventh chords. Specifically in what category would a diminished triad topped with a major seventh fall? Can it be considered a half-diminished 7th? All music theory sources i've checked clearly indicate that half-diminished 7th chords can only be topped with a minor. So what type of chord do you get by laying down a major 7th over a diminished triad? Thank you

  • 5 types? Maj7, m7, dom7, dim7, m7b5, mM7,
    – Tim
    Commented Aug 28, 2020 at 6:01
  • It won't be a 'half-diminished' chord. Those have a diminished triad (e.g. C Eb Gb) with m7 (Bb) added. AKA 'm7b5'. Yours would be 'mM7b5'.
    – Tim
    Commented Aug 28, 2020 at 7:50

2 Answers 2


dimMaj7. It’s quite uncommon. But its component notes are enharmonics of tones in a different, more common chord.

The tones in CdimMaj7 (C, E-flat, G-flat, B) are enharmonic equivalents of four fifths of a B7flat9 chord (B, D#, F#, A, C).


Just to add a bit to this post, another way of conceptualizing this chord is a triad with a b2 in the bass (i.e. B/C). This diminished chord along with the maj7th melody note is a defining part of the song “Spring is Here” by Rogers and Hart.

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