A cis man, or cisgender man, is a man whose gender identity corresponds to the sex they were assigned at birth. In other words, a cis man is someone who identifies as male and was assigned male at birth. The term "cis" is a Latin prefix meaning "on this side of," and is used as an antonym to "trans," which refers to someone whose gender identity does not correspond to the sex they were assigned at birth. It is important to note that being cisgender does not necessarily mean that a person is heterosexual, as sexual orientation and gender identity are separate aspects of a persons identity.