Cisgender is used as a term to contrast with transgender, usually meaning a person who identifies with their socially assigned gender. That's how I've come to know it, at least. :)
(Cis in Latin means something like "on this side" or "hither".)
No one's been upset, Fox - it's just how the rules are. I'm very sorry about your situation IRL, I sincerely hope things work out for you. :/
On another note: 25 rereads of the series? Holy crap that's... massive.