Third gender or third sex is a concept in which individuals are categorized, either by themselves or by society, as neither man nor woman. It is also a social category present in societies that recognize three or more genders. The term third is usually understood to mean "other"; some anthropologists and sociologists have described fourth, fifth, and "some" genders.
Biology determines whether a human's chromosomal and anatomical sex is male, female, or one of the uncommon variations on this sexual dimorphism that can create a degree of ambiguity known as intersex. However, the state of personally identifying as, or being identified by society as, a man, a woman, or other, is usually also defined by the individual's gender identity and gender role in the particular culture in which they live. Not all cultures have strictly defined gender roles.
In different cultures, a third or fourth gender may represent very different things. To the Indigenous Māhū of Hawaii, it is an intermediate state between man and woman, or to be a "person of indeterminate gender". The traditional Dineh of the Southwestern US acknowledge four genders: feminine woman, masculine woman, feminine man, masculine man. The term "third gender" has also been used to describe hijras of India, Bangladesh and Pakistan who have gained legal identity, fa'afafine of Polynesia, and sworn virgins of the Balkans.