Like the
abbreviation bi for bisexual, pan is an
abbreviation for pansexual.
Pan generally refers to the
sexual orientation of someone that can love or be attracted to a person of any sex, not just females or males, including but not limited to males, females, transexuals, tansvestites, gender benders, hermaphrodites, intersexuals, androgenous people, and those with sex-chromosome anomaly such as klinefelter syndrome or turner syndrome.