Shur

an enclosure; a wall, a part, probably, of the Arabian desert,
on the NEern border of Egypt, giving its name to a
wilderness extending from Egypt toward Philistia (Gen. 16:7;
20:1; 25:18; Ex.15:22). The name was probably given to it from
the wall (or shur) which the Egyptians built to defend their
frontier on the NE from the desert tribes. This wall or
line of fortifications extended from Pelusium to Heliopolis.