The belief that there are multiple gods.
Most ancient religions were polytheistic, exceptions being Judaism, Christianity, Islam, Atenism. The belief in multiple gods does not imply the worship of multiple gods. Many polytheists believe in the existence of many gods, but worship only one. This variant of polytheism is termed henotheism. Some people view henotheistic polytheism as a form of monotheism; practically all Jews and Muslims, however, view henotheism as polytheism.