Shen, which means to encircle or surround, is a stylized representation of a rope circle. It is an ancient Egyptian symbol of protection. The cartouche is a variant of the Shen symbol. This symbol was carved around names of kings and other important individuals not only to protect them in general, but also to keep the engraved name from being used in witchcraft to harm the person.
The Shen also represented eternity and was worn as an amulet in and of itself. It was thought to safeguard against spiritual or magical harm.