Eclipsian, also known as sollunarian, is a non-binary gender from the galactian alignment system. It is a combination of solarian and lunarian. An eclipsian individual can be fluid between the two genders or can be both at the same time.
It is unknown who coined this term and when, however it has been used since December 5, 2016.
The eclipsian flag was posted on Tumblr by user Temp-Nb-Blog on December 5, 2016 along with the other combination flags. It has no confirmed meaning.