Originally Posted by: psmc1214parenthesis around a note or chord notes means what?

In both tabs and sheet music, this is usually a ghost note or an optional note. A lot of times it's used for a root or bass note in a chord that doesn't have to be played, for example:

E|-----
B|--1--
G|--2--
D|--3--
A|--3--
E|-(1)-

Hope this helps!