A familiar is traditionally understood as a spirit connected to a witch, sometimes taking the shape of a cat, toad, bird, dog, or other animal. In folklore and literature, familiars may carry messages, provide magical knowledge, spy on others, or assist with spells. A familiar is not simply a pet; it is usually portrayed as having supernatural intelligence, powers, or spiritual significance.

The idea of familiars became especially prominent in European witch-trial accounts of the sixteenth and seventeenth centuries, where accused witches were said to receive animal-shaped spirits from the Devil. In poetry and other imaginative writing, a familiar can symbolize hidden knowledge, instinct, companionship, danger, or a character’s connection to the supernatural. Related terms include spirit guide, animal familiar, imp, and witch’s companion. Not every animal associated with a witch is necessarily a familiar; the term implies a magical or spiritual bond.