'Horn' in the Bible

Now a man of wickedness was found there whose name [was] Sheba the son of Bichri, a Benjaminite. He blew the horn and said, "There is no share for us in David, and there [is] no inheritance for us in the son of Jesse; each to his tents, O Israel!"

The woman went to all of the people with her wise plan, so they cut off the head of Sheba the son of Bicri and threw [it] to Joab. Then he blew the horn and dispersed from the city, each to his tent. Then Joab returned to Jerusalem to the king.