Meaning

noun the title of the Holy Roman Emperors or the emperors of Austria or of Germany until 1918

originInherited from Middle English kayser, from Old High German keisar (“emperor”), from Proto-West Germanic *kaisar, from Proto-Germanic *kaisaraz. The native Old English descendant of that Proto-Germanic word was cāser (“emperor”), but the shape of Middle English kayser (“emperor”) (versus the expected *caser, *coser) suggests it was borrowed from another Germanic language rather than inherited, and…

Etymology from Wiktionary, CC BY-SA 3.0