Morrish Bible Dictionary 
These are referred to in scripture as
1. On the altar, the projections placed at its corners, on which the blood of the sacrifices was placed, and to which culprits clung for protection. Exodus 38:2; Leviticus 4:7; 1 Kings 1:50 .
2. For trumpets, especially rams' horns. Joshua 6:4-13 .
3. For holding oil. 1 Samuel 16:1,13 .
4. For holding ink. Ezekiel 9:2,3 .
5. They were worn in the East as a symbol of exaltation and power. Jehovah was David's horn of salvation. He exalted the horn of His people, and brake the horns of the wicked. Psalm 18:2; Ps.75:10; Ps.148:14.
6. Horns are spoken of frequently in Daniel and the Revelation as a symbol for kings: "the ten horns which thou sawest are ten kings." Daniel 7:7-24; Daniel 8:3-21; Revelation 12:3; Revelation 13:1; Revelation 17:3-16 .
Hawker's Poor Man's Concordance And Dictionary