What does a number inside a parentheses in a chord name mean? Here are some examples I have found: B(7)#9b9 no 5, Ab(7) #9#11 no R, A(7)b9sus no b7 .

For context, I found them on this James Hober paper, starting at page 6: The 43 Four-Note Qualities


4 Answers 4


It's normal to write altered chord extensions, and to some degree altered chord notes, in parentheses. The (minor or major) sevenths though, are normally never parenthesized.

However James Hober uses some unusual notation. This is a consequence of that there are some unusual chords or chord voicings that he is trying to represent.

If you look carefully you will find that the only figure that is parenthesized in his list is the 7. Further you will find that in all instances of chord voicing names that has this parenthesized 7 it is also stated that it is omitted ("no b7").
(Example: "B(7)#9b9sus+ no R, b7" meaning the chord B-E-G-A-C-D with the root 'B' and the b7 'A' omitted, leaving the notes C-D-E-G. (I would like to see the functional analysis that would arrive at calling this voicing by this name rather than just Cadd9 or perhaps G6sus4...))

Why then does he list the 7 in parentheses when it also says it is omitted? It's perhaps because he has interpreted that the additional chord extension notes are to be seen as extensions to a dominant chord, and perhaps also that calling most of them added tones would be quite unorthodox.

So the parenthesized sevens you see in James Hober's list are merely an indication that the chord can be considered a dominant chord, but that is missing the dominant seventh.

  • Note: For normal notation of chords the parentheses around chord extensions are merely there for improved readability and does not signify lesser importance, and certainly not that they are to be omitted. Omitting extension notes or other notes could however be done by the discretion of the performer. Commented Dec 5, 2013 at 1:07
  • Yes, in my experience, chords that tell you to omit a note are usually in an "analysis" context where you try to be as exact as possible. If you were to give that instruction to an improviser, they would most likely just ignore it unless the chord by nature was extremely limiting and specific (i.e. a heavily modified pentatonic scale or something). But even then, chords are guidelines to an improviser, a skilled one can make any consonance/dissonance work for them. Commented Dec 6, 2013 at 22:38

The number in a parenthesis isn't strictly equated to a Dominant seven per se. When music is written by hand, the use of parenthesis is used just to make groups of notes and "alterations" more clear to the reader, so it's a matter of preference. Unlike in computer science where syntax is non-negotiable, there are many ways to convey formal concepts in music, especially when referring to music theory and chord alternations.

There is a common convention though in music that if you just list a 7, you're implying a dominant seven (flatted 7). You would have to specify "Major 7" or "Maj7" or "M7" or the triangle Aebersold notation used in the paper itself depending on your notation preference to get an unaltered "Major 7".

So to use your first example:

B(7)#9b9 no 5

This is a B major, dominant 7, with a sharp 9, a flat 9, and omit the 5th.

I personally would have written it like this (on a computer)

B7(#9,b9, no 5)

Because B dominant 7 is a very common chord, so it is in a sense, the "core" of the cord. Then alterations would follow after.

If written by hand I might have made the 7 a subscript, and the alterations in parenthesis as a superscript to increase the clarity, similar to this:

B7(#9,b9, no 5)


The reason for parenthesis is clearly to denominate options (ad libitum) that dont go thru the whole measure:

  • D(m) is d - g with ad libitum alternating f/f♯
  • Dm2 is d - e - a
  • Dm(2) is d - f - a with ad libitum alternating e/f
  • Dm4 is d - g - a
  • Dm(4) is d - f - a with ad libitum alternating f/g
  • Dm(2/4) is d - f - a with ad libitum alternating e/f/g
  • Dm2(4) is d - e - a with ad libitum alternating e/g
  • Dm9(4) is d - e - f - a with ad libitum alternating f/g
  • Dm9(4) is d - e - f - a with ad libitum alternating f/g
  • Dm11(2) is d - f - g - a with ad libitum alternating e/f
  • Dm11(9) is d - f - g - a with ad libitum added e

So yes, there is a defined System, but it might be that few really understand it. You can do that for any modificator to denominate a modification that depends on the melodical structure of the part you want to key with the chord, so instead of writing:

| C | C ; C7 | G |

you just trust the musicians experience (and the perhaps already given melodic notes below) and just write:

| C | C(7) | G |


| C | C7 | G |

would really mean: if someone filling it with strings on the keyboard, please fill with c-e-g-b♭ for the whole measure.


I believe it means a dominant chord with its alterations. Dominant meaning the 7th degree is flat.

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