Mercurian is a non-binary xenogender in the celestial gender system. It is linked to a soft, celestial energy that is neither masculine or feminine. The energy may feel gendered but it is not masculine nor feminine. Mercurian people may feel different amounts of gendered energy at different times. Someone who is mercurian can also be void of gender itself.
The term mercurian was coined by the Tumblr user Fallenangelkinblr. The flag was designed by Tumblr user Juparian and was posted on November 1 2017. An alternate version of the flag was designed by System-Lgbt in October of 2018. The color more closely resemble colors of Mercury.
The root of mercurian is Mercury. Historically Mercury has been associated with non-binary genders. The symbol for Mercury (☿) is often used as a symbol for a third gender.