Omnisexual (often shortened to omni) is an orientation defined as the sexual attraction to all genders, though gender still plays a role in the attraction. This can also be a romantic orientation (omniromantic).
Omnisexuality vs. Pansexuality
Lots of people in the LGBT+ community are uneducated on the many forms of non-monosexuality (attraction to more than one gender) and are very confused when they see the terms pansexual and omnisexual side-by-side, however there is a distinction between them.
Pansexual people are gender-blind, meaning gender does not play a role in the attraction and they are attracted to people no matter their gender; they don't recognize it.
Omnisexual people are also attracted to all genders, much like pansexuals, but they are not gender-blind. Omnisexuals do recognize the gender of the person they are attracted to, and for some, it is a major factor in attraction. For some, it isn't, but they are still not gender-blind if they call themselves omnisexual.
Some may think that the distinction isn't necessary, but it is to lots of people. Please let everyone define their own orientation as they wish, and don't dictate the labels that other people get to choose.
The word omnisexuality appears as early at the 1959 beat poet Lawrence Lipton's The Holy Barbarians, but the first time it was described in the context of the current definition was in a 1984 text titled simply Sexual Choices: An Introduction to Human Sexuality. This text described omnisexuality as "a state of attraction to all sexes," stating that some researchers believe that every individual is born omnisexual before developing their sexual attraction into the labels of homosexual, heterosexual or other orientations.
The term spread even further in the early 1990's as M. Jimmie Killingsworth undertook an analysis of the poet Walt Whitman. In Killingsworth's study, he found that Whitman had a general omnisexual character throughout his work The Leaves of Grass. In the 2010's, The Atlantic noted that his poetry expresses sexuality towards all genders, sometimes even the sea or the Earth.
Omnisexual was a common message board term in the 2000's. The knowledge of this term was boosted even further when several celebrities, such as Janelle Monae and Brendon Urie, came out as pansexual. The media made several non-monosexual terms known in the mainstream as that took place. Many popular articles discussed omnisexuality alongside these celebrities' pansexuality.
Some fictional characters, such as Jack Harkness from Doctor Who, the Marvel character 'Deadpool' have has been canonically confirmed as omnisexual.
The prefix omni- comes from the Latin word omnis, meaning 'all'. Pan-, which the term pansexual comes from, also means ’all’, and is a Greek prefix.