A plurality exists when a chord has more than one harmonic context or usage. This concept applies to all triad and most 7th chords that are commonly used in jazz repertoire.

This is great for simplifying voicings of complex chords onto the fret-board of the guitar, being a notoriously hard instrument to ‘visualise’ chords on. If you spend some time studying these shapes and relationships you’ll be able to voice chords and lines along much simpler to ‘see’ and play chordal positions, by thinking of the primary triads or 7th chords at the top of the voicing; rather than trying to voice all the notes of a written chord (or settling for common voicings etc).

Listed below are the most commonly used primary and secondary ‘plural series’ of triads > 7th chords > 9th chords.

Primary plurality:

1. C major has the notes C, E, and G, add an A below and they now form the top 3 notes of an Ami7 chord.

2. C major has the notes C, E, and G, add an Ab below and they now form the top 3 notes of an Abma7(#5) chord.

3. C minor has the notes C, Eb, and G, add an Ab below and they now form the top 3 notes of an Abma7 chord.

4. C minor has the notes C, Eb, and G, add an A below and they now form the top 3 notes of an Am7(b5) chord.

5. C diminished has the notes C, Eb, and Gb, add an A below and they now form the top 3 notes of an A dim7 chord.

6. C diminished has the notes C, Eb, and Gb, add an Ab below and they now form the top 3 notes of an Ab7 chord.

7. C augmented triad has the notes C, E, and G#, add an A below and they now form the top 3 notes of an Ami(ma7).

So we have constructed a basic ‘chord series’ by adding a 3rd below the tonic of each chord in the series. Therefore a C triad could = Am7 OR Ab+ma7!

https://truefire.com/guitar-lab/putting-sus-chords-to-work/chord-plurality-pt-1-isus2–vsus4/v40830

Secondary plurality:

8. Abma7 has the notes Ab, C, Eb and G, add an F below and they now form the top 4notes of an Fmi9 chord.

9. Abma7 has the notes Ab, C, Eb and G, add an E below and they now form the top 4 notes of an E+ma7(#9) chord.

10. Ab7 has the notes Ab, C, Eb and Gb, add an E below and they now form the top 4 notes of an E+ma9 chord.

11. Am7 has the notes A, C, E and G, add an F below and they now form the top 4 notes of an Fma9 chord.

12. Ami7(b5) has the notes A, C, Eb and G, add an F below and they now form the tope 4 notes of an F9 chord – or tritonally substitute the bass (F) to a B to form the top part of a B+7(b9) chord.

13. Ab+ma7 has the notes Ab, C, E and G, add an F below and they now form the top 4 notes of an Fmi(ma9) chord.

14. Ami(ma7) has the notes A, C, E and G#, add an F# below and they now form the top 4 notes of an F#mi9(b5) chord.

We now add a note below to form a 9th chord from some of the 7 chords given above. Learn the relationships from 9th to 7th to triad chords also, i.e. Fm9(b5) = Abmi(ma7) = B+ triad. There are also many more plural forms in common use, some of which will be covered in a Master Class Video here on JGL in the near future.