'Horn' in the Bible

All you peoples of the world, and you who are living on the earth, when a flag is lifted up on the mountains, give attention; and when the horn is sounded, give ear.

And it will be in that day that a great horn will be sounded; and those who were wandering in the land of Assyria, and those who had been sent away into the land of Egypt, will come; and they will give worship to the Lord in the holy mountain at Jerusalem.

Make a loud cry, do not be quiet, let your voice be sounding like a horn, and make clear to my people their evil doings, and to the family of Jacob their sins.