Paganism is the Name given by the Christians of the end of the Roman Empire to polytheist cultures.
The term has historically been used as a pejorative by adherents of monotheistic religions (such as Judaism, Christianity and Islam) to indicate a person who doesn’t believe in their religion.
Paganism frequently refers to the religions of classical antiquity, most notably Greek mythology or Roman religion.
Pagan was also describing an Epicurean.
There have been some attempts to classify the Paganism subdivision.
One of them is by Isaac Bonewits ( http://www.neopagan.net ):
Paleo-Paganism: A Pagan culture that has not been disrupted by other civilizations or other cultures. This does not include any known cultures. Indeed, this absolutely, by definition, cannot include any sort of living culture, since all cultures have been “disrupted” by their neighbours to some extent or another.
Meso-Paganism: A group, which is, or has been, influenced by a conquering culture, but has been able to maintain an independence of religious practices. This includes Native Americans and Australian Aborigine Bushmen.
Syncreto-Paganism: A culture, which has been conquered but adopts and merges the conquering culture’s religious practices with their own. This includes Haitian Vodoo and Santería .
Neo-Paganism: An attempt by modern people to reconnect with nature, pre-Christian religions, or other nature-based spiritual paths. This definition includes Ásatrú, Neo-Druidism and Wicca .
the belief that personalized supernatural beings (or souls)
Recognize some truth in all faith systems, highlighting agreements and minimizing differences