I’ve seen many attempts at trying to define what Traditional Witchcraft is since it recently became popularized through the internet and book publishing, but most of those definitions seem to only include what it is not or are extremely ambiguous and misleading. The most common definitions tend to say that it is a) British Isles traditional witchcraft (Ireland, Scotland, Wales, Cornwall, England, etc) of the “anything but Wicca” variety; b) European-based traditional witchcraft (usually just Germanic, Celtic, Basque, Italian, and Greek witchcraft and folk magic), but not neoPaganism or reconstructionism, and is also of the “anything but Wicca variety”; c) a long-established tradition of witchcraft (tradition, however, being used in the modern sense stemming from its use for Wiccan traditions), usually referring to hereditary witchcraft both fictional and non-fictional – the latter being more of the folk magic or hereditary psychic ability category; d) and lastly the more ambiguous anything but Wiccan, non-neoPagan, non-fluffy, non-religious, “craft” or “skill” of witchcraft usually practiced by solitaries.
The above explanations really don’t do it for me (as I prefer my definitions sans Wicca-bashing) and also do not explain well how the term is applied today compared to what the term actually represents when it comes to a path or tradition of magic and spirituality of today. I suggest, based on my own experience, research, and having been in the Traditional Witchcraft community before there were really any books or websites on the subject (at least with the words “traditional witchcraft in the titles”), that there are two separate definitions of Traditional Witchcraft just as when one looks up any word in the dictionary there is usually more than one possible meaning. Here are the two I have found to be used by practitioners and groups overall, or at least, how they intended to define it:
Definition 1 – “Traditional Witchcraft”: A modern witchcraft, folk magic, or spiritual practice based on the practices and beliefs of witchcraft in Europe and the colonies from the early modern period which ranged from the 1500s to the 1800s. The beliefs and practices were usually the pre-Christian remnants of more ancient Pagan or Animistic ones surviving to the early modern period through oral fairy & folk tales, ballads, songs, rhymes, superstitions, rural traditions, and various grimoires. However, there really were practicing 
witches, folk magicians, and magical groups during this time, but their practices and beliefs would have been tinged with Catholic-Christian overtones and mythology – even if thinly veneered on top of the Pagan ones. This does not mean there is a long-established tradition of an unbroken line of witches practicing within Paganism, but rather that just small fragments of what “might” have come before remained even if the witches and superstitious peasants themselves didn’t know it (which they likely did not). Cunning folk are a good example of the survival of such traditions even up to the mid-1900s in rural areas of the British Isles. But it is the magical traditions in the colonies that really thrived even into modern times such as Curanderismo in Hispanic America which is a unique combination of Spanish folk magic and the folk magic and herbalism of the local peoples as well as Haitian Vodou which stems from a combination of West African spiritual beliefs, Arawakian religious beliefs, and the Roman Catholic Christianity of the French and Spanish colonizers in the Caribbean.
Definition 2 – “Modern Traditional Witchcraft”: Traditional Witchcraft as a modern accepted term used to refer to a specific witchcraft path and traditions within it which did not exist until the early 2000s. Before this time period there was no literature or groups claiming this label the way it is used today, but many influences for modern Traditional Witchcraft came beforehand in a period from the 1950s to the 1970s. These earlier influences most commonly included Robert Cochrane, Paul Huson, Joe Wilson, Robert Graves, and Victor Anderson. The later most common 
authors whose influence led to the creation of and modern definition of Traditional Witchcraft from a period of time from the 1980s to the 2000s includes E. J. Jones, Michael Howard and his periodical The Cauldron, Nigel Jackson, Nigel Pennick, Andrew Chumbley (post-2000) and Daniel Schulke (post-2000) — the later authors largely being influenced by the former. There are also more recent internet-savvy popular writers who now have their own cult followings due to the lore and hard work of the groundbreaking men who came before them. Most modern witches who claim they practice Traditional Witchcraft are mainly influenced by Chumbley’s Sabbatic Witchcraft, the writings of Robert Cochrane (also via Joe Wilson and E. J. Jones), and the practices and beliefs of Paul Huson in his work Mastering Witchcraft – whether they know or acknowledge it or not as the lore from these men may have come indirectly through another person or resource.
All other witchcraft and magical traditions not based in early modern witchcraft, modern traditional witchcraft, or British traditional witchcraft (Wicca) belong more to the realms of culture-based folk belief/religion, shamanism, and animism than they do to traditions of witchcraft.
For more information and resources see the article on Traditional Witchcraft
