Cyclopedia of Biblical, Theological and Ecclesiastical Literature
(Hebrews Etham', אֵתָם, supposed by Jablonsky [Opusc. ed. to Water. 2:157] to be i.q., Coptic atiom, i.e., "boundary of the sea;" Sept. Ο᾿θώμ, but omits in Numbers 33:8; Vulg. Etham), the third station of the Israelites when they left Egypt; a place described as lying "in the edge of the wilderness," where they encamped after the journey from Succoth (Exodus 13:20; Numbers 33:6). This description, and the route pursued by them, seem to fix upon some spot on the east of Egypt, north of the Red Sea, near the desert tract stretching thence along the whole eastern shore as far as Marah, to which the same name, "desert of Etham," is therefore naturally applied in the text (Numbers 33:8). The precise locality of Etham has been a matter of dispute, according to the various theories of the passage across the sea. No spot more likely has been indicated than a point in the valley of the bitter lakes opposite the foot of wady AbuZeid, in the direct route around the point of the sea, but from which there is a passage sharply deflecting, up wady Ena-shesh, around Jebel Attaha, which the Israelites were at this point commanded to take. (See EXODE); (See DESERT).
The sense of the passage Numbers 33:6-8, is evidently this: At the end of the second day they had already arrived at the bolders of the Arabian desert, at Etham, from which the tract of country lying next to Egypt receives the name, desert of Etham; but, instead of advancing directly into the desert, they turned down again farther into Egypt, to the Arabian Gulf. Afterwards, instead of going round the sea, they proceeded through it into the desert of Etham. (See SHUR). Schwarz says (Palaest. page 211) that the part of the desert north of the Red Sea, near Suez, is still called Ethia, but this lacks confirmation.
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McClintock, John. Strong, James. Entry for 'Etham'. Cyclopedia of Biblical, Theological and Ecclesiastical Literature. https://www.studylight.org/encyclopedias/eng/tce/e/etham.html. Harper & Brothers. New York. 1870.