A person whose gender identity aligns with the sex they were assigned at birth.
Definition
A person whose gender identity aligns with the sex they were assigned at birth. "Cis" is Latin for "on the same side." A neutral descriptive term - not a slur.
Etymology
Latin cis- (on the same side) + gender. First used in academic literature by Volkmar Sigusch (1994) and Dana Leland Devor (1995). Added to the Oxford English Dictionary in 2015 and Merriam-Webster in 2017.
History
Before "cisgender" existed, there was no neutral word for people whose gender identity matched their sex assigned at birth - they were simply called "normal," implicitly framing transgender people as abnormal. Trans activists argued a parallel, neutral term was needed. The term is now standard in academic, medical, and community contexts.