Hebrew word in Revelation 16:16 meaning "Mount Megiddo." It is generally thought that the term refers to the town of Megiddo. Megiddo is located between the western coastal area and the broad plain of Jezreel in northern Palestine.
The area of Megiddo was important commercially and militarily. Many important battles in Israel’s history took place in Megiddo:
There the Lord routed Sisera before the armies of Deborah and Barak (Judges 4–5).
Gideon was victorious over the Midianites and Amalekites (Judges 6–7).
King Saul and his army were defeated by the Philistines (1 Samuel 31).
King Josiah was slain in battle by the Egyptian army of Pharaoh Neco (2 Kings 23:29).
Because of that long history, the name Armageddon has become symbolic of a battlefield.
Armageddon in the Book of Revelation
Revelation 15 and 16 describe seven angels who pour out seven bowls of the wrath of God upon the earth. The sixth angel pours out his bowl upon the great river Euphrates, and its waters are dried up (Revelation 16:12–16). This action prepares the way for the coming of the "kings of the East."
Three demonic spirits go forth to cause the kings of the whole world to gather for a battle on the great day of God the Almighty (Revelation 16:13–14). Their gathering takes place at Armageddon (Revelation 16:16). See Revelation, Book of.