The Shen / Shenu Ring gets its name from the Egyptian word "shenu", that literally means to encircle. This symbol was used in text and inscriptions to protect the subject within the ring. It was believed that the ring offered an eternal divine protection for its contents.
The symbol could be stretched to contain other objects, which were also understood as being eternally protected by the Shen ring. In its elongated form the ring became the cartouche, which enclosed and protected a royal name.