'Lower' in the Bible

Then it will happen on that day that the LordWill again acquire with His hand a second timeThe remnant of His people, who will remain,From Assyria, from [Lower] Egypt, from Pathros, from Cush (Ethiopia), from Elam [in Persia], from Shinar [Babylonia], from Hamath [in Aram],And from the coastlands bordering the [Mediterranean] Sea.

You saw that the breachesIn the wall of the City of David [the citadel of Zion] were many;You collected [within the city’s walls] the waters of the Lower Pool (Siloam).