early 14c., from French sans, Old French sen, sens (with adverbial genitive) "without, except, apart, not counting," cognate with Provençal senes, Old Catalan senes, Old Spanish sen (Spanish sin), Old Italian sen, from Vulgar Latin *sene, from Latin sine "without," enlarged form of sed, se "without" (from PIE root *sen(e)- "apart, separated;" see sunder). In reference to fonts, 1927, short for sans-serif.
trimethyl-derivative of xanthine, 1830, from German Kaffein, coined by chemist F.F. Runge (1795-1867), apparently from German Kaffee "coffee" (see coffee) + chemical suffix -ine (2) (German -in). So called because the alkaloid was found in coffee beans; its presence accounts for the stimulating effect of coffee and tea. The form of the English word may be via French caféine. Related: Caffeinic.