Revelation 12:3

The second "sign" John saw was the "dragon" whom God identified in Revelation 12:9; Revelation 20:2 as Satan. "Dragon" (Gr. drakon) occurs 12 times in the New Testament and only in the Book of Revelation. In every instance it refers to Satan (Revelation 12:3-4; Revelation 12:7; Revelation 12:9; Revelation 12:13; Revelation 12:16-17; Revelation 13:2; Revelation 13:4; Revelation 13:11; Revelation 16:13; Revelation 20:2). A dragon symbolizes a powerful, aggressive, deadly foe. His red color suggests bloodshed. [Note: Newell, p. 172; Moses Stuart, A Commentary on the Apocalypse, p. 621; Lange, p. 246; Scott, p. 337.] His seven heads and ten horns probably represent seven nations and ten rulers (Revelation 17:12). Ten kings will rule under his authority, but when Antichrist rises to preeminence among them he will subdue three of them, leaving only seven (Daniel 7:7-8; Daniel 7:20; Daniel 7:24; Revelation 13:1). The seven royal crowns (Gr. diadema) picture the political authority of these seven rulers during the Great Tribulation.

A less literal interpretation regards the ten horns as simply symbolic of the dragon’s mighty strength.