And they had a king over them, [which is] the angel of the bottomless pit, whose name in the Hebrew tongue [is] Abaddon, but in the Greek tongue hath [ his] name Apollyon.
Berean Study Bible (BSB) - Revelation 9:11 >They were ruled by a king, the angel of the Abyss. His name in Hebrew is Abaddon, and in Greek it is Apollyon.
Textus Receptus (TR) - Revelation 9:11 >Καὶ ἔχουσιν ἐφ᾿ αὐτῶν βασιλέα τὸν ἄγγελον τῆς ἀβύσσου· ὄνομα αὐτῷ Ἑβραϊστὶ Ἀβαδδών, καὶ ἐν τῇ Ἑλληνικῇ ὄνομα ἔχει Ἀπολλύων.