Bigender is a non-binary gender identity is with someone has two distinct gender identities. They could feel both genders at the same time or be fluid between them. If a bigender person feels that their identity changes over time they may also identify as genderfluid. The two genders could be male and female, however they could be any combination of two genders, including non-binary genders. People who identify as more than two genders can be multigender.
Bigender people may also identify as transgender, but not necessarily.