Etham

perhaps another name for Khetam, or "fortress," on the Shur or great wall of Egypt, which extended from the Mediterranean to the Gulf of Suez. Here the Israelites made their third encampment (Ex 13:20; Num 33:6). The camp was probably a little to the west of the modern town of Ismailia. Here the Israelites were commanded to change their route (Ex 14:2), and "turn" towards the south, and encamp before Pi-hahiroth. (See EXODUS; PITHOM)

EBD - Easton's Bible Dictionary