What is Wicca?
Wicca, sometimes called "The Craft" or "The Craft of the Wise" is one of many earth-based religions. The religion which is closest to Wicca in America is probably Native American spirituality. Traditional Wicca was founded by Gerald Gardner, a British civil servant, who wrote a series of books on the religion in the 1940's. It contains references to Celtic deities, symbols, seasonal days of celebration, etc. Added to this were components of ceremonial magic and practices of the Masonic Order. A more recent form is eclectic Wicca which involves a combination of Wiccan beliefs and practices, combined with other Pagan and non-Pagan elements. The various traditions of Wicca are part of the Pagan or Neopagan group of earth-based religions.
Because Wicca is such an open-minded religion, only the very basics are shared by all practitioners: worshipping both a Goddess and a God, revering nature, practicing magic to better people's lives, and abiding by the Wiccan Rede. Most other details vary considerably. Some consider initiation mandatory to be a Witch, others do not. Some do not use specific names for Deities and simply call them "Goddess and God", while others pick names that suit their beliefs in ancient mythologies. Some worship in groups called "covens", but many (if not most) are solitary practitionners. There are even a few witches who don't practice magic at all and focus only on pagan worship, yet they may still call themselves Wiccan if their beliefs fit in the syncretistic "constellation" of Wicca.