We add a 7 to the letter:
We add Maj7, 7 o
:
We add min7, m7 or -7:
We add dim7 or o7:
We add 7,
o m7(b5):
As with the triads, to indicate an inversion, we add a slash and specify the note that should be played in the bass:
See also: Triads, Ninth Chords, Other Extensions