Centilliogender is a multigender, that is a subset of mathgender, in which one feels as though they have, experience, or encompass a centillion genders. It should be noted that centillion has no consistent definition. American dictionaries site it as 10303, while British dictionaries site it as 10600. Presumably either definition could be used, because the coiner never clarified which was intended. It is similar to billiogender, kilogender, platilligender, trilligender, and zilliogender. It may also be considered a subset to pangender.
Centilliogender was coined on July 31, 2018 by Tumblr user arco-pluris.
The horizontal and vertical stripes split the flag into an almost innumerable amount of individual parts to represent the extremely large amount of individual genders experienced, and the pi symbol represents the seemingly unending complexity and vastness of centilliogender.