In Latin "trans" means "the other side" and "cis" means "this side."
The only real English word I can point to for demonstration is "cismontane" to describe someone or something that is on the same side of a mountain as you are.
Because Bruce Jenner is a man who wants to pretend to be a woman he is called a "transwoman" in academic jargon, whereas Kate Upton, who is a woman and apparently happy to be one, is a "ciswoman."
Cis/trans isomerism (geometric isomerism, configurational isomerism) is a term used in organic chemistry to refer to the stereoisomerism engendered in the relative orientation of functional groups within a molecule.