What are cis and trans alternate types of? I don’t think it’s “gender identity” because wouldn’t that just be man, woman or nonbinary regardless of whether they’re cis or trans? Cis/trans just being a qualifier?
If the answer is “I am cis” or “I am trans”, what is the question?
Edit: Someone came up with the term “gender congruity” and (after looking up the definition of “congruity”) I think this describes what I’m talking about perfectly.
You can think of ‘cis’ and ‘trans’ as meaning roughly ‘this side’ and ‘other side’.
In a gender context the ‘sides’ are male and female and the items are physical gender and mental gender. If both genders are on the same side, both on ‘this side’, that’s ‘cis’. If they are different, one ‘this side’, one ‘other side’, that’s ‘trans’.
So, if the answer is “I am cis/trans” the question is “Is your mental gender the same as your physical gender?” “I am cis” then means “My mental gender is the same as my physical gender” and “I am trans” means “My mental gender is not the same as (or maybe ‘is opposite’) my physical gender”.
Note that ‘physical gender’ is not always clear. Some people are born with ambiguous genitalia and may be surgically altered to make their genitalia more closely resemble the commonly recognized pattern for ‘male’ or ‘female’, and some may be left as-is. In some cases this can be a reason for a trans gender identity.
Before “cisgender” became a widely publicized term, about the only time I ever heard the term “cis” was discussing Cisalpine versus Transalpine Gaul in ancient Rome. (Cisalpine Gaul being northern Italy and Transalpine Gaul southern France, more or less - the parts of Gaul that were on the same side or the opposite side of the Alps from Rome).
Chemistry. Cis-2-n-ene vs Trans-2-n-ene. First one is all carbons on the same side and the latter is carbons on opposite sides.