A similar term to "cis" is "heterosexual". This adjective was also coined in the early 20th century, although its original use was far less neutral than "cis".
In 1901, "heterosexual" first appeared in Dorland's Medical Dictionary, meaning “abnormal or perverted appetite toward the opposite sex". In other words, hererosexuality was considered pathological when it was first coined!
In 1934, the definition of "heterosexual" was revised to its current definition, and no longer considered a pathology.