To the anon asking why cisgender is a term: 'cis' is just the opposite of 'trans' no matter if its related to gender or not! Cis is just latin for "on this side of" and trans is latin for "on the other side of." A good example of this is the words 'cismontane' (meaning on this side of the mountain) and 'transmontane' (meaning on the other side of the mountain. Same with cisatlantic and transatlantic. So any word with a prefix of 'trans' has a theoretical opposite starting with 'cis'!
Kevin says: yeah and cis-trans isomers in chemistry! just means same side or other side of the molecule!!