DÉET (DÉE.T). — An archaic Egyptian form (d'à.t; Coptic tê) denoting the underworld. In early times the Egyptians, observing that the stars rose and set at such distant points on the earth, believed that beneath it there was a narrow, circular tunnel through which they passed.
This idea was modified when the sun was assigned a boat and it was thought that by night it traversed this tunnel. The river is also called d. But since the d. was also regarded as the dwelling-place of the dead, from the 18th Dynasty onward the Book of What is in the d. (improperly called Am-Duat) provides an illustrated guide to the twelve regions which the solar barque traversed during the night. The names of these regions, their dimensions, inhabitants, and the various perils, had to be known by the deceased for his spiritual benefit.