In Witchcraft, three cords are used. They are each nine feet in length and usually red in color, although in some traditions, one cord is red and the others are different colors. Similarly, some traditions have only three coven cords, which are kept on the altar, while other traditions allow each and every coven member to have his or her own personal cord or cords. In the latter case, the cord(s) may be worn about the waist as a cingullum.
The cord has many uses, including marking the circle by sticking a knife into the ground and looping the cord around it at its halfway point. Holding the White Handled Knife at the extremities of the doubled cord, it can then be moved around, marking the ground, while keeping the cord taut. This would result in a perfect nine foot diameter circle.
The cord is also used for knot magic, or tying knots into it as part of a ritual where power has been raised. Power would be charged into each knot put into the cord. In this fashion, the power could be released at a later date by untying the knots.
The cord is also used to bind Initiates in Wiccan Initiations. Symbolically the binding represents the restriction of the womb before birth.