Bidemigender or demibigender is a combination of bigender and demigender. In other words, it is when one identifies as two demigenders. Bidemigender people can be a combination of any two demigenders. For example, a bidemigender person could be a demiboy and a demigirl.
History
The term was coined by Tumblr user MOGAI-Monarchs on or before September 1, 2020, alongside pandemigender, polydemigender, quaddemigender, quintdemigender, and tridemigender.[1]
It was separately coined on the LGBTA fandom wiki by Wikia user Trashwoof on December 20, 2020.