What does Sela, Selah mean in the Bible?

Dictionary

Morrish Bible Dictionary - Sela, Selah
The rock city of Edom. 2 Kings 14:7 ; Isaiah 16:1 . The same Hebrew word is that usually translated 'rock.' The place was taken by Amaziah, who called it JOKTHEEL, q.v. It is judged to be the same as PETRA (which occurs in the margin of Isaiah 16:1 ). Petra is a remarkable place. Though about two thousand feet above the sea, it is shut in by mountain-cliffs, and is entered by a narrow ravine, through which also the river winds. The tombs cut in the rocks are large, especially one called el Khuzneh, which has three rows of columns. The tiers of a theatre remain, a triumphal arch, and ruined bridges. There is a sort of awe-inspiring grandeur in the place. Petra lies 30 22' N, 35 43' E .