Multigender is a term for someone who experiences two or more genders. It falls under the non-binary and transgender umbrellas. It can be used as a gender identity on its own or can be an umbrella term. This includes bigender (two genders), trigender (three genders), quadgender (four genders), and so on, all the way up to pangender (all genders).
Multigender people may experience these genders identities at the same time, or their gender identity may change over time, making them genderfluid. If a person experiences experiences fluctuation in the intensity of those genders, they could possibly be multiflux. The genders they experience can be male, female and/or any non-binary identities.
Multigender is often used interchangeably with polygender, however some people define polygender as having more than two genders, so bigender is included in multigender but is not included in polygender.
Flag
The multigender flag was made by deviantart user Pride-Flags on Jan 16, 2016. It is unknown if it has a meaning.