Kaiser is the German title meaning "Emperor". Like
the Russian Czar it is directly derived from the Roman Emperors' title of
Caesar, which in turn is derived from the personal name of a branch of the gens
(clan) Julia, to which Gaius Julius Caesar, the forebear of the first imperial
family, belonged. Although the British monarchs styled "Emperor of
India" were also called "Kaisar-i-Hind" in Hindi and Urdu, this
word, although ultimately sharing the same Latin origin, is derived from the
Greek Kaisar, not the German Kaiser.
In English, the term the Kaiser is usually reserved for the
Emperors of the German Empire, the emperors of the Austrian Empire and those of
the Austro-Hungarian Empire. During the First World War, the term the Kaiser —
especially as applied to Wilhelm II of Germany — gained considerable pejorative
connotations in English-speaking countries.