Is there such a thing as...

Is there such a thing as a C2 Chord? or G2 etc? I've found several songs that have these listed as a chord, but i can't find it anywhere. So What I'm wondering is, Is it real, and if it is, How do you play it?
# 1

usually i see that in guitar tab books, but above the notes and tablature where they give you chords and strumming patterns...when you look at the beginning of the song they have chords used in it with chord boxes (usually above the title of the song) and if they have a C chord in it, then have a C power chord they'll just call it C (for the straight chord) and CII (for the power chord)...hopefully i explained it right for ya
# 2

I may be wrong on this, but I think C2 and D2 are the same as Csus2 and Dsus2, which means you add the 9 (the 2 of the root's octave) instead of the 3rd usually. Look for some chords charts with these names. I'd do it here, but it's hard to replicate w/o a monospaced font.
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# 3

Ekstasis is right. The only distinction between a 2 chord and a 9 chord is that a 9 chord must have the third, and the seventh is implied as well. A 2 or sus2 chord does not have the third or the seventh.
# 4

here is the simple no-theory answer:
a C2 has the 2 note of the C scale.
the 2 note of the C scale is D.
so, a C2 has a D.
I like to play it like this:
a C2 has the 2 note of the C scale.
the 2 note of the C scale is D.
so, a C2 has a D.
I like to play it like this:
E |-------------------------------|
B |-----------3-(d)---------------|
G |-----------0-(g)---------------|
D |-----------2-(e)---------------|
A |-----------3-(c)---------------|
E |-------------------------------|
# 5

# 6

I think you are right. But I get the feeling that most tabs don't make that fine a distinction. So, I would just play that Cadd9 and think of it as a C2. But I am a real shortcut artist, and maybe I should be more exact.
Here is a C2 with no 3rd (no e). The difference in this chord and the one before, IMO, is pretty subtle.
Here is a C2 with no 3rd (no e). The difference in this chord and the one before, IMO, is pretty subtle.
E |-------------------------------|
B |-----------3-(d)---------------|
G |-----------5-(c)---------------|
D |-----------5-(g)---------------|
A |-----------3-(c)---------------|
E |-------------------------------|
# 7