Terminology
The term comes from the Greek poly ("many") and theoi ("gods") and was first invented by the Jewish writer Philo of Alexandria to argue with the Greeks. When Christianity spread throughout Europe and the Mediterranean, non-Christians were just called Gentiles (a term originally used by Jews to refer to non-Jews) or pagans (locals) or, in a clearly pejorative idolaters (worshiping "false" gods). The modern usage of the term is first revived in French through Jean Bodin in 1580, followed by Samuel Purchas's usage in English in 1614.
Read more about this topic: Polytheism