Exodus 13:20

Etham - The house or “sanctuary of Tum” (the Sun God worshipped especially by that name in Lower Egypt), was in the immediate vicinity of Heliopolis, called by the Egyptians the fortress of Zar, or Zalu (i. e. of foreigners); the frontier city where the Pharaohs of the 18th dynasty reviewed their forces when about to enter upon a campaign on Syria. The name Pithom (see Exodus 1:11) has precisely the same meaning with Etham, and may possibly be identified with it.