The Witch’s knot is a common symbol in folk magic. The witch’s knot is a symbolic representation of the knot magic practiced by witches in the middle ages, and was used as a sympathetic charm against witchcraft, and usually scratched over doorways of homes and stables. One aspect of its efficacy as a protective charm lay in the ability to draw the complicated symbol in one continuous motion.
While the symbol appears to be made up of intertwined vesica pisces, it does not represent “feminine powers” as is sometimes claimed, but the inversion of those powers- the four radiating half circles symbolically reflect malefic winds. Ironically, this is a popular emblem of choice for modern witches.