In Egyptian belief, names express the fundamental nature of the things to which they refer. In keeping with this belief, the names of deities often relate to their roles or origins. The name of the predatory goddess Sekhmet means "powerful one", the name of the mysterious god Amun means "hidden one", and the name of Nekhbet, who was worshipped in the city of Nekheb, means "she of Nekheb". Many other names have no certain meaning, even when the gods who bear them are closely tied to a single role. The names of the sky goddess Nut and the earth god Geb do not resemble the Egyptian terms for "sky" and "earth".