Cogender

Cogender is a term with at least three known possible definitions.

Gender Identity
Cogender is a gender which is the mathematical union of two genders, as opposed to venngender; the intersection of two genders. A cogender person is okay with being identified as either of the genders included in their identity, including a combination of the two. It's possible for someone to be cogender and not realize it at first, because one of their genders happens to be the gender they were assigned at birth.

A format of expressing this identity is "X co Y" where X and Y are genders. For example, girl co boy.

A variation on this identity is cofluid, which is a genderfluid version of cogender. For a cofluid person, one part of their identity is static but the other part(s) change. For example, a cofluidboy has a cogender identity that always includes male, but the other identity(s) vary.

This term was coined on August 25th, 2016, on the Tumblr blog Cogender. The term comes from the Latin root co meaning “with" or "together".

In Anthropology
Some anthropologists use cogender as a synonym for third gender, that is to say, as an umbrella term for gender variant and LGBT roles and identities in various cultures.

When anthropologists write about shamanic traditions among the indigenous Mapuche (Araucana) people of Chile, they use co-gender to talk about roles that the machi (shamans) take on during their spiritual practice. Historically, as well as today, machi can have had any gender assigned at birth, and their practice involves ritual cross-dressing in order to communicate with certain aspects of their Creator as needed. At different times, they dress to take on a wife role for a male aspect of that deity, or to take on a husband aspect for a female aspect of that deity. The machi becomes part of a male-female pair with the Creator. As concerning "co-gendered identities" of "machi as co-gender specialists", the machi themselves have often been categorized as Two-Spirit, meaning indigenous gender roles that don't correspond to Western ideas of the strictly cisgender, heterosexual gender binary.

Anthropologists writing about cosmologies in which everything is characterized as having female and male aspects have referred to this as a co-gendered cosmos. Based on the primordial male-female deity couple, "in highland Guatemala, husbands and wives are trained together as shamans by a shaman couple. [They are taught to] recognize both cosmic co-gendering and their own co-gendered nature [...] they learn how to properly balance the feminine and masculine dimensions both within their own bodies and the cosmos."

Gender Inclusion
Cogender is sometimes used to show the inclusion of people of different genders in a community, as opposed to a men-only or women-only community. This is the most common way this word is used. When used in print, it's usually in reference to a co-gender school (also called co-education) or to a co-gender LGBT activist group (as opposed to a lesbian-only activist group).