In ancient Egyptian tombs, a small, concealed chamber in which the ka statue of the deceased was placed.

saqqara_zoser_serdab01View into the serdab, Step Pyramid of Djoser, Saqqara, Egypt. Ca. 2681-2662 BCE. The ka statue is a replica of the original now in the Egyptian Museum, Cairo. Photo: Tore Kjeilen/LookLex.