According to Medieval Christian doctrine, a Witch is a person, usually a woman, who sells her soul to the Devil in order to obtain magical powers.
The Witch often has a demon familiar who helps her out, watches over her and makes sure she maintains her loyalty to Satan.
There may be Witches in the world who practice this way but they are few and far between.
Satanism is a religion that does not usually (but may) involve Witchcraft and demonology is a different type of lore altogether.
Diabolism exists independent of witchcraft, and while there’s no reason a witch couldn’t engage in it, the two practices are not inherently related.
There are some Christians who consider themselves witches and incorporate withcraft into their Christian religious observances or practice it as a secular activity quite separate from religion.
