Pansexual, from the Greek for All, today means someone who is sexually attracted to any gender, whether male, female, trans, androgynous, etc. Today's sociosexual term generally is used to describe anyone who doesn't base their sexual attraction to someone on their sexual gender or identity.

The origin of the term had quite a different meaning. Back in the days of Freud, Pansexual was not a choice, personal taste, or way of looking at things. Rather, being a Pansexual was a disorder. I do not mean a disorder like Homosexuality used to be seen as a sickness. Pansexual was the result of severe brain trauma. This was not their explanation of things at the time. This was a now medically understood disorder.

The brain trauma caused the person to be incapable of discerning the difference between a woman with her legs spread wide open on a bed and... let's say, a tree. I am not kidding, nor is this hyperbole. The person's brain, due to the neurological damage, no longer had the ability to differentiate between one thing or another being sexually arousing. Instead the person would be sexually aroused towards virtually anything & everything; hence Pansexual.