cis

Etymology 1

From Latin cis (“on this side (of), on the near or same side”). Doublet of he, it, here, hither, and hence.

adj

1. (biology) Having two mutations on two genes on the same chromosome of a homologous pair.
2. (cytology) Of the side of the Golgi apparatus nearer to the endoplasmic reticulum.
3. (chemistry) In (or constituting, forming, or describing) a double bond in which the greater radical on both ends is on the same side of the bond.
   9 is thought to survive longer when the CH = CH bond is cis and to favour the formation of another cis double bond in a propagation reaction involving its displacement by monomer. 10, on the other hand, is more likely to yield a trans double bond […] 1984, American Chemical Society. Division of Polymer Chemistry, Papers Presented at the ... Meeting
   However, a cis double bond causes a kink in the chain. (A cis double bond introduces a bend of about 42 into the linear hydrocarbon chain.) 2007, Vickie A. Vaclavik, Elizabeth W. Christian, Essentials of Food Science, Springer Science & Business Media, page 277
   A cis double bond is one where the hydrogen atoms are both on the same side. In contrast, a trans double bond has them on the opposite side. 2015, William P Edwards, The Science of Bakery Products, Royal Society of Chemistry, page 26
4. (chemistry) In (or constituting, forming, or describing) a coordination compound in which the two instances of a particular ligand are adjacent to each other.
   The cis effect is the labilization of ligands which are cis to certain other ligands.

Etymology 2

Clipping of cisgender or cissexual, ultimately from Latin cis.

adj

1. Cisgender (or sometimes cissexual): not trans (transgender or transsexual) nor non-binary.
   Coordinate term: trans
   We're demonized and criminalized as perverts out to trick and deceive cis hetero men; therefore anything that happens to us, we 'had coming.' 2017-11-21, Trish Bendix, quoting Ashlee Marie Preston, “Why it matters that transgender women are speaking out about Jeffrey Tambor — and that people are listening”, in Yahoo! Lifestyle
   Oh yeah, because you know who's been long overdue a challenge? The trans community. Oh, they've had their guard down for too long if you ask me. They'll all be checking their privilege on the way home now thanks to you, you brave little cis boy! 2019-01-17, James Acaster: Cold Lasagne Hate Myself 1999, spoken by James Acaster
   The reality is that LGBTQ+ people face challenges at disproportionally higher rates than their straight counterparts — drug use, sex work, and financial instability can be an unfortunate result. My privilege as a young cis white man whose parents weren't going to let me drown afforded me the ability to make those mistakes and live to talk about it. 2019-09-24, Johnathan Van Ness, Over the Top: A Raw Journey to Self-Love, HarperCollins, pages 117–118