Omnisexual is an orientation defined as the sexual attraction to all genders. Omniromantic is the romantic attraction to all genders.
Omnisexuality often goes hand in hand with pansexuality, although the two are separate identities. The main difference between the two is that pansexuals do not see gender, or do not care about gender. On the other hand, omnisexuals do see gender, but are still attracted to all genders and are often attracted to people because of their gender.
The prefix omni- comes from the Latin word omnis, meaning 'all'. Pan-, which pansexual comes from, also means ’all’, and is a Greek prefix.