Same chord, different voice:

E - 0
B - 1
G - 0
D - 0
A - 3
E - X

_________________

Just think of how awesome a guitar player you could have been by now if you had only spent the last 10 years practicing instead of obsessing over pickups and roasted maple necks.

or, my personal favorite (especially playing a "D-variation song):
e - O
B - 3
G - O
D - 2
A - 3
E - X

_________________

Okay, I think I have the term "C2" somewhat figured out. It's kind of what I assumed. Thank you guys.

By the way, for clarification- the way I've learned it is that a sus4 chord doesn't simply add the 4th, but it replaces the 3rd with the 4th.

So, when I see a sus2 chord, I think of the 2nd as a replacement for the 3rd. In other words, a Csus2 would contain the notes CDG as opposed to a C major, which would contain the notes CEG.

If, for instance, you simply add the scale degree in question to the chord, it might be an "add9" (aka Mu Major, for any Steely Dan fans) for a chord containing CEGD or an "add11" for a chord containing CEGF. In my mind, however, the latter might be more appropriately named Fmaj9 in a diatonic context. Although the lack of a third makes for some ambiguous voicings.

Incidentally, I was questioning the validity of the term "sus2" earlier. I've had teachers say it wasn't really an accepted thing (in the world of jazz). I'm not really sure about that so I took him for his word.

However, I just remembered that long ago I once discovered that (what my understanding of) a sus2 and a sus4 are just inversions of the same thing. For example a Csus4 (CFG) would be the same as an Fsus2 (FGC). So as far as I'm concerned it seems like a handy way to indicate an inversion when writing a tune.

I hope I haven't caused any confusion