*ko-

word-forming element meaning "on the near side of, on this side," from Latin preposition cis "on this side" (in reference to place or time), related to citra (adv.) "on this side," from PIE *ki-s, suffixed form of root *ko-, the stem of demonstrative pronoun meaning "this." Opposed to trans- or ultra-. Originally only of place, sometimes 19c. of time; 21c. of life situations (such as cis-gender, which is attested by 2011).

also etcetera, early 15c., from Latin et cetera, literally "and the others," from et "and" + neuter plural of ceterus "the other, other part, that which remains," from Proto-Italic *ke-etero‑, from *ke-, variant form of PIE root *ko-, the stem of demonstrative pronoun meaning "this" + *etero‑ "other (of two), again, a second time, again," a PIE adjective of comparison.

The common form of the abbreviation before 20c. was &c., but etc. now prevails.