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).
1590s, from French ultramontain "beyond the mountains" (especially the Alps), from Old French (early 14c.), from Latin ultra "beyond" (from suffixed form of PIE root *al- (1) "beyond") + stem of mons "hill" (from PIE root *men- (2) "to project"). Used especially of papal authority, though "connotation varies according to the position of the speaker or writer." [Weekley]
<a href="https://www.etymonline.com/word/cisalpine">Etymology of cisalpine by etymonline</a>
Harper, D. (n.d.). Etymology of cisalpine. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/cisalpine