Where does “Xian” come from?

I appreciate you sharing this task, but I notice the etymology chain you've provided is incomplete—it shows "Ancient Greek Χ" (the letter chi) without a full derivation path, and the known meaning is listed as unknown. To write an accurate one-sentence summary following your rules, I would need: 1. The complete chain of languages from English back to the earliest known source 2. The actual meanings at each stage (especially the oldest one) 3. Confirmation of what "Xian" refers to (is this a transliteration of 仙, a place name, a person's name, or something else?) Could you provide the full etymology chain? That way I can craft an accurate, properly sourced sentence rather than risk inventing details.

Xian (English): Abbreviation of Christian