Thermosphenic is a term used to show how close or far one is from the gender binary. Thermosphenic describes someone who considers themselves to be mostly removed from the gender binary, but still having some small connection to it. For example, one might be a thermosphenic lunarian, or a thermosphenic enboy.
Thermosphenic was coined on December 17, 2019 by Tumblr user Biohazardmogai. The original flag was created at the same time. The term thermosphenic comes from the word thermosphere, the second farthest layer of the atmosphere. The flag with the stars was an edit made by Tumblr user hadalpelagic--zone on the same day.