Witchcraft, in historical, anthropological, religious, and mythological contexts, is the alleged use of supernatural or magical powers. A witch (from Old English wicca masculine, wicce feminine) is a practitioner of witchcraft. Historically, it was widely believed in early modern Christian Europe that witches were in league with the Devil and used their powers to harm people and property. Particularly, since the mid-20th century, "bad" and "good" witchcraft are sometimes distinguished, the latter often involving healing. The concept of witchcraft as harmful is normally treated as a cultural ideology, a means of explaining human misfortune by blaming it either on a supernatural entity or a known person in the community.
Supernatural
Witches are very powerful beings that have the power to effect change by magical means ("witchcraft"). Keeping with historical usage, "Supernatural" seems to reserve the term "witch" for practitioners of black magic. In Malleus Maleficarum, witches receive their power from Demons - presumably in exchange for their souls. It is notable that Sam, Dean, and Bobby often use the same spells and rituals, but would not consider themselves witches.
With the advent of religions such as Wicca, "witchcraft" has taken on a more value-neutral meaning and encompasses the practice of both good and evil magic -- people who in previous centuries would have been called "wise wo/men" or "cunning wo/men" are now the the term "witch."
The Vampire Diaries
A witch is a person with the power to effect change by magical means ("Witchcraft"). A Witch can be either male or female, as they connect with the elements and forces of nature, in order to practice sorcery.
Buffy the Vampire Slayer
Witch was a term that referred to female human magic practitioners. Their male counterparts were known as warlocks. Witches were capable of harnessing mystical forces usually through spells and rituals, and even by force of will in the case of more experienced witches.
While some witches, such as Willow Rosenberg, were the only witches in their family and obtained their power through training alone, others seemed to have inherited a talent for magic from their mothers, such as Amy Madison and Tara Maclay. Some witches were stronger than others, with Willow Rosenberg being described by Anya as "the most powerful Wicca in the western hemisphere". As stated by Aluwyn, witches drew their powers from external forces including other dimensions, and so they lost the ability to control magic when the Seed of Wonder was destroyed and Earth was cut off from the rest of the multiverse.
Willow tempted in Dark Magic
The Secret Circle
The origin of the witchcraft race remains a mystery, but it is known that the Blake Family are one of the first, and most powerful witches in existence. For many centuries, witches have existed, passing down their knowledge and skills through generations of family lines.
Harry Potter
Wizardkind are humans born with the ability to use magic. An individual male human with magical ability is known as a wizard (plural: wizards), and an individual female human with magical ability is known as a witch (plural: witches), though "wizard" is sometimes used as a gender-neutral singular noun like "man".