The words emperor, caesar, czar, and Kaiser all go back to one source: the title of the first Roman emperor, Imperator Caesar Augustus. Augustus was the adopted son of the Roman general and ruler Julius Caesar and he took the name Caesar as part of his official name. Later Roman emperors did the same, and thus caesar came to mean “an emperor of Rome.” The word caesar was borrowed into German and other Germanic languages as Kaiser, which is how we get the word kaiser for “a ruler in Germany.” Through the Russian word tsar, which also came from kaiser, we got our word czar, meaning “a ruler in Russia.” The word emperor can be traced through French to Latin imperator. Imperator was a title given to great Roman generals and meant “commander,” from the verb imperare “to command.”