What chord is this? And what does N.C. mean?

[beermonkey]

No it can't, if A(add 9 omit 3) is the sound the composer is looking for from the instrument that's playing that chord. If you were on a gig and you ran across this notation, you probably had better play what's written, because there may be a very good reason why the chord is notated in that way.

If it's notated as A(b9 omit3), that is exactly what you should play. I was gathering from his question that he was asking the much more general question of "what chord do these notes make". Without more information, those three notes do not make up only one definite chord.

 

[Aaron]

My guess is that it is most likely a Gb7#9 or C13 because that's how I'd do a rootless voicing for one, being it has the 3rd/7th and color tone (just omitting the root and fifth, which a bassline would be covering.)