'Brook' in the Bible

“The south side toward the south shall extend from Tamar as far as the waters of Meribath-kadesh, to the brook of Egypt and to the Great Sea. This is the south side toward the south.

And beside the border of Gad, at the south side toward the south, the border shall be from Tamar to the waters of Meribath-kadesh, to the brook of Egypt, to the Great Sea.