This is from our own Wiki section on the site:
Pansexuality, or omnisexuality, is a sexual orientation, characterized by the potential for aesthetic attraction, romantic love, or sexual desire towards people, regardless of their gender identity or biological sex. Some pansexuals suggest that they are gender-blind; that gender and sex are insignificant or irrelevant in determining whether they will be sexually attracted to others. For others, an individual's sex, gender expression, or gender identity can be a key factor of attraction, despite the pansexual individual's wide range of sex and gender attractions.
The word pansexual is derived from the Greek prefix pan-, meaning "all". It is intended to negate the idea of two genders (as expressed by bi-).
The adjective pansexual may also be applied to organizations or events. In this context, the term usually indicates an openness to the involvement of people of all genders and sexual orientations in said organization/event, as well as the pansexual sexual identity.
Edited to remove footnotes