Keras (G2768) means a horn — the animal horn that serves as a weapon and symbol of power. In biblical symbolism, the horn represents strength, authority, and royal power. It appears prominently in apocalyptic literature as a symbol of kings and kingdoms.
Zechariah praises God for raising up 'a horn of salvation (keras sōtērias) for us in the house of his servant David' (Luke 1:69) — Christ is the horn of power and deliverance. In Revelation, horns represent power on the beasts and on the Lamb: 'He had seven horns and seven eyes' (Revelation 5:6). Lifting the horn (Psalm 92:10) is a metaphor for exaltation; cutting off the horn is defeat. The Lamb with seven horns has all authority.