The term cis-woman is used in reference to one whose gender identity is consistent with their gender as perceived at birth. Typically, this means that the person in question was born with a vulva (though not necessarily a vagina as infant sexual identification is based on external sexual characteristics) and was pronounced female and now identifies as such.
Before the term cis-woman came into use, the existing language referred to "women" and a "trans-women." This was problematic as it implied that one was the baseline while the other represented a deviation and thus something inherently lesser. Now, the term cis-woman is a complementary term to trans-woman and allows for recognizing that there are multiple ways to be a woman.
