Omni-Sapphic is a label under the Omnisexual umbrella. It is mixing two different labels (Omni and Sapphic), while also not using harmful labels such as Omni-Lesbian. It is when a woman, or woman-aligned nonbinary person may be attracted to all genders, but they prioritize their attraction to women and/or women-aligned people. This does not mean that the user of the term is a Lesbian/Trixic, this just means that the user of the term has a preference to women.
History
The term Omni-Sapphic can be traced to the Tumblr user “kokichisleftasscheek”, on October 22, 2020.
Flag
The flag meaning is as such, starting from the bottom:
Light blue - Attraction to male-aligned nonbinary people.
Blue - Attraction to men.
Black - Attraction to nonbinary people.
Deep Pink - Attraction to women.
Pink - Being a woman.
Light Pink - Being woman-aligned
Light Pink/Purple - Attraction to women/women-aligned people
Etymology
The term Omni-Sapphic comes from the Latin prefix “Omnus-“, meaning “all”, and the word Sapphic, coming from Sappho, who was a woman who loved other women.
Resources
https://kokichisleftasscheek.tumblr.com/post/632718817947172864/omni-sapphic-omni-achillian