Cis is a thing, deal with it
In modern sociological discourse it is. It was actually coined by Julia Serrano, who ... has probably been mentioned in this thread.
cis being used in sociology, or by trans people or allies, doesn't mean anything about whether anyone should adopt it.
it's interesting, no one can tell me why "non-trans(gender)" isn't a completely acceptable replacement for "cis(gender)".
it's because they aren't identical terms. cisgender means everyone "has a gender identity", and, it's completely harmonious.
i don't have a "gender identity", am estranged from the social ideas of womanhood, but i'm a woman because i'm female.
cis is an ingenious trick to make people feel like this lack of affiliation makes you trans/NB, and that you should transition.
it's an unwanted label that groups you into an "innate gender" without consent, ironic because they say they value agency.
non-trans also can't ever be used as a pejorative, or a way to frame non-trans people as oppressing trans people either.
it's also
only for relevant cases. the reality is we are people without a rare condition (troonism), so, we are average people.
edit: also, yes, julia serrano is a creepy third wave troon who sparked a lot of issues with the movement, so i won't use it.