'tain't that easy, Mom - My 1997 Webster's New World Dictionary describes pagan as a person who is not a Christian, Jew, or Muslim.
A Web search for "paganism" brings up information that might be more relevant. Click here for what looks like an interesting page.
Here (click) is another resource which gives a lot of information, including this quote:

Paganism is a broad, eclectic contemporary religious movement that encompasses shamanistic, ecstatic, polytheistic, and magical religions. Most of the religions termed Pagan are characterized by nature-centered spirituality, honoring of pre-Christian deities, dynamic, personal belief systems, lack of institutionalization, a quest to develop the self, and acceptance and encouragement of diversity. Paganism is sometimes referred to as Neo-Paganism to emphasize its connections to as well as difference from pre-Christian religions.

Paganism is a worldwide phenomenon and includes revived and updated ancient European practices and religions, feminist Goddess-worship, and religions inspired by science-fiction writings. For their inspiration, Pagans look to non-Abrahamic, ecstatic, and mystery religions of Europe as well as indigenous and magic-using traditions from around the world. Contemporary Paganism is interwoven with artistic, visionary, and libertarian traditions and emphasizes the free will of the individual. Many traditions celebrate rituals to mark transitions in the natural world (such as solstices, lunar phases, or a birth) as well as in a person's life (such as marriage or moving to a new home).

While the largest segment of the Pagan population is Caucasian and middle class, Paganism cuts across all lines, whether racial, occupational, or class- or gender-based. Most Pagans, however, are avid readers with interests in ecology, creativity, and personal growth. Many come from the scientific, computer, and technical fields. Since it is not an organized movement, it is very difficult to determine the number of its practitioners, but it is estimated that there are between 100,000 and 600,000 in the U.S. alone. Some have termed Paganism the fastest-growing religion in the West.

-Joe Offer, still waiting for admission as a Plaid Pagan-