Literally.  (1/3rd)

“Fallen” Angels (in Christian, Jewish, and Muslim tradition) an angel who rebelled against God and was cast out of heaven.

https://twitter.com/TheFigen/status/1080150455777415168

The Fifth Trumpet—the Bottomless Pit

Revelation 9:1  Then the fifth angel sounded, and I saw a star from heaven which had fallen to the earth; and the key of the bottomless pit was given to him.