Cisgender (often abbreviated to simply cis) is a term for people whose gender identity matches the sex that they were assigned at birth. Cisgender may also be defined as those who have “a gender identity or perform a gender role society considers appropriate for one’s sex”. It is the opposite of the term transgender
German sexologist Volkmar Sigusch used the neologism cissexual (zissexuell in German) in a peer-reviewed publication. In his 1998 essay “The Neosexual Revolution”, he cites his two-part 1991 article “Die Transsexuellen und unser nosomorpher Blick” (“Transsexuals and our nosomorphic view”) as the origin of the term. He also used the term in the title of a 1995 article, “Transsexueller Wunsch und zissexuelle Abwehr” (or: “Transsexual desire and cissexual defense”).
Cisgender has its origin in the Latin-derived prefix cis-, meaning “on this side of”, which means the opposite of trans-, meaning “across from” or “on the other side of”. This usage can be seen in the cis–trans distinction in chemistry, the cis–trans or complementation test in genetics, in Ciscaucasia (from the Russian perspective), in the ancient Roman term Cisalpine Gaul (i.e., “Gaul on this side of the Alps”), and more recently, Cisjordan, as distinguished from Transjordan. In the case of gender, cis- describes the alignment of gender identity with assigned sex.