Pansexuality?

As

Will you help me understand?? I've been told that pansexuality is when you like anyone regardless of gender. I'm getting this confused with bisexuality. Unless bisexuality is when people who are attracted to people that act/dressed of their assigned gender and pansexual means they're open to people that act/dressed as their assigned gender AND transsexuals as well? I'm sorry if this is offensive, I'm genuinely curious about what it means.