X-ray <
a translation of german X-strahlen < X (= unknown quantity in maths) + Strahlen, plural of Strahl (= beam, ray).
xanthic < french xanthique (= yellowish) < ancient greek
ξανθός | ksanthos (= yellow).
xebec < french chébec (= small three-masted vessel) < italian sciabecco < arabic shabbak (= a small warship).
xenophobia < ancient greek ξένος | ksenos (= foreign, strange) + french -phobia
( < latin -phobia < ancient greek -φοβία | -phobia (= fear of) < φόβος | phobos (= fear) < φέβομαι | phebomae (= go away fearing)).
xerasia < late latin xerasia
< ancient greek ξηρασία | ksērasia (= dryness) < ξηραίνω | ksēraenō (= to dry) < ξηρός | ksēros (= dry, withered).
xerography < ancient greek ξηρός | ksēros (= dry) + γραφία | -graphia (= a writing) (< γράφω | graphō (= write, draw)).
xiphias < ancient greek ξιφίας | ksiphias (= swordfish) < ξίφος | ksiphos (= sword).
Xmas (= Christmas) [1551] < X’temmas
< X (< ancient greek X (= khi [pronunciation]), as an abbreviation for Χριστός | Khristos (= Christ) [also Xρ- | Xr- for Chr-] + anglo-saxon Xres mæsse [= Christmas] {< ancient greek [Ιησούς] Χριστός | Khristos (= the Anointed) < χρίω | khriō (= to rub, anoint)}.
xylophone < ancient greek ξύλον | ksylon (= wood) + φωνή | phōnē (= sound).
xyster < ancient greek ξυστήρ | ksystēr (= a graving tool) < ξύω | ksyō (= to scrape).
