Any of various notable people with this name as given name or surname, especially Saint Francis Xavier, a Spanish Catholic saint and missionary (1506–1552).
Xaver
xanthine
/ˈzanθaɪn/, /ˈzanθiːn/, /ˈzænθin/
noun
(chemistry) Any of a group of alkaloids that include caffeine, theophylline, and theobromine as well as the parent compound, a precursor of uric acid found in many organs of the body.