x

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 | xanthos (= yellow).
xebec < french chébec (= small three-masted vessel) < italian sciabecco < arabic shabbak (= a small warship).
xenophobia < ancient greek ξένος | xenos (= foreign, strange) + french -phobia (< latin -phobia < ancient greek -φοβία | -phobhia (= fear of) < φόβος | phobhos (= fear) < φέβομαι | phebhomae (= go away fearing)).
xerasia < late latin xerasia < ancient greek ξηρασία | xērasia (= dryness) < ξηραίνω | xēraenō (= to dry) < ξηρός | xēros (= dry, withered).
xerography < ancient greek ξηρός | xēros (= dry) + -γραφία | -ghraphia (= a writing) (< γράφω | ghraphō (= write, draw)).
xiphias < ancient greek ξιφίας | xiphias (= swordfish) < ξίφος | xiphos (= sword).
Xmas (= Christmas) [1551] < X’temmas < anglo-saxon Xres mæsse (= Christmas) {X < ancient greek X (= khi [pronunciation]), as an abbreviation for Χριστός | Khristos (= Christ)} < ancient greek [Ιησούς] Χριστός | [Iēsous] Khristos (= the Anointed) < χρίω | khriō (= to rub, anoint) < I.E. *ghrei- (= to rub).
xylophone < ancient greek ξύλον | xylon (= wood) + φωνή | phōnē (= sound).
xyster < ancient greek ξυστήρ | xystēr (= a graving tool) < ξύω | xyō (= to scrape).