Kaiser is the German title meaning "Emperor," with Kaiserin being the female equivalent, "Empress." It is directly derived from the Latin Emperors' title of Caesar, which in turn is derived from the name of Julius Caesar.In English "the Kaiser" is usually reserved for the Emperors of the German Empire. Although the British monarchs styled "Emperor of India" were also called "Kaiser i Hind" in Hindi and Urdu, this word, although similar in form, has no direct relationship with German Kaiser.See M. Witzel, "Autochthonous Aryans? The Evidence from Old Indian and Iranian Texts", p. 29, 12.1  (as Urdu kaisar).
German history and antecedents of the title
The Roman imperial style was revived in the Frankish realm by Charlemagne in 800. When his empire was divided the title of Emperor went to the ruler holding the kingdom of Rome. Through inheritances this kingdom fell to the eastern ("German") kingdom. The Holy Roman Emperors (962?1806) called themselves Kaiser, combining the imperial ti
Source: http://en.wikipedia.org/wiki/DER KAISER