The Greek ordinal adjective ennatos (ἔννατος) means ninth. In Jewish time-keeping, the ninth hour corresponds to approximately 3:00 PM. While numerically unremarkable, the ninth hour carries enormous theological weight in the Gospels and Acts.
The ninth hour is the hour of Christ's death: "And about the ninth hour Jesus cried with a loud voice" (Matthew 27:46). It was also the established hour of afternoon prayer in Second Temple Judaism (Acts 3:1). The ninth hour of the Atonement — the hour of Israel's prayer — becomes the hour of the world's salvation. God answers the corporate prayer of the ages with the cross.