snow-fury-deactivated20170226:

I don’t know if this is entirely correct but as far as I know, it’s like this:

Bisexual:  sexual attraction to both the opposite and same sexes such as man to man and man to woman, woman to woman and woman to man. As far as I know, bisexuals are attracted to people who are biologically male and female, which separates them from pansexuals. 

Pansexual: sexual attraction towards people regardless of gender also known as omnisexuality, some pansexuals refer to themselves as gender blind as to them gender is  insignificant in determining whether they will be sexually attracted to others.

There is also Polysexuality - the sexual attraction to more than one gender but do not wish to be known as bisexual as it implies that their are only two binary sexes, do not confuse this with pansexuality (Pan meaning All) and (Poly meaning many).

So, I think bisexuals are attracted to people who are biologically male and female, polysexuals are attracted to multiple genders and pansexuals are attracted to anyone regardless of gender. I hope that’s correct and makes sense.

Source

I dont want to sound rude or anything but i thought i’ll add more info and correct some stuff here.

I am pansexual so I am not to be quoted on the other sexualities but from what I’ve read the most used definitions are:
Bisexual: Attracted to two or more genders. (I’ve also seen to the same and others genders)
Pan: Attracted to all genders (some are attracted regardless of, some do have preferences but ‘all genders’ is the core of the orientation. Also to note, the term “genderblind” is not to use since it erases one’s gender identity wich is really important to some people)
Also Omni- and Pan- are not the same thing, I’m not sure myself of the exact definition of omni- though so I can’t add more info, sorry. I’ve tried browsing the ‘omnisexuality’ tag to grasp the definition but most posts used out-dated definitions of pansexuality so I’m not sure.

As far as I’m concerned, the polysexuality definition seems alright, someone correct me if I’m wrong.

Saying that bisexual are only attracted to “biological” girls and boys is biphobic and transphobic, since it implies that transwomen are not “real” women and transmen not “real” men and putting in the definition of bisexual that they are transphobic (basically) is biphobic. It also enforces the gender binary even though bisexuals can be attracted to non-binary individuals (some bisexuals are not and that’s ok)

To sums it up, bisexuals are attracted to two or more genders, polysexuals to many genders and pansexuals to all genders. Omnisexuals also exists but I’m not quite sure where they fall in, once again sorry for that.