A somewhat vague term derived from from the Latin word paganus. Pagan is a term which refers to a variety of different religions ranging from Wicca, to that of ancient Egypt and even Hinduism, among many others. Some Pagans are of no specific religion, but rather are eclectic. In general Pagan religions have more than one deity, or many gods which are aspects of one (an idea similar to that of the Christian trinity). Another quite common feature of Pagan religions are that they tend to be nature oriented. Pagan can also be used as a derogatory word for any non-Judeo/Christian/Islamic religion.
"The religion of the ancient Greeks is a Pagan religion"