The term pansexual can take on a variety of different meanings depending on which social group the term is being used in, but it is generally defined as someone who is attracted to other people regardless of their gender or sexual orientation. The word pansexual is used as an inclusive term as opposed to bisexual, as bisexuality only refers to people liking both men and women, and does not including a wider variety of gender neutral or gender fluid terminology.
Pansexual can also refer to an organization, event or group. In this situation, the pansexual is defined as meaning open or welcome to all genders and not referencing one's sexual orientation or gender.
Occasionally, pansexuality is defined as a person who displays their sexuality in many different ways, or as someone who is open to a variety of sexual activities, although both of these definitions have become rare.
Etymology:
The word pansexual comes from the greek prefix pan-, which translated means "all".
Pansexuals differ from bisexuals in that they are attracted to not just men and women, but also transgendered, androgynous and gender fluid persons.
"Pansexuals have the capability of attraction to others regardless of their gender identity or biological sex. A pansexual could be open to someone who is male, female, transgender, intersex, or agendered/genderqueer." - Queers United, Diversity Lesson 101: Pansexuality
"Pansexuality is attraction on a more spiritual level, one might say, and focuses on who the target of affection is, rather than "what," as do other sexualities." - Urban Dictionary

