horn

• horn
• 1

  animal

• a) [countable] the hard pointed thing that grows, usually in pairs, on the heads of animals such as cows and goats [↪ antlers]
• b) [uncountable] the substance that animals' horns are made of:
• a knife with a horn handle
• c) [countable] a part of an animal's head that sticks out like a horn, for example on a snail
• 2

  on a car

   [countable] the thing in a vehicle that you use to make a loud sound as a signal or warning
• sound/toot/honk/blow your horn (=make a noise with your horn)
• 3

  musical instrument

   [countable]
• a) a musical instrument like a long metal tube that is wide at one end, that you play by blowing
• b) informal a trumpet
• c) a French horn
• d) a musical instrument made from an animal's horn ➔ English horn
• 4

   drinking horn/powder horn etc

  a container in the shape of an animal's horn, used in the past for drinking from, carrying gunpowder etc
• 5

   draw/pull in your horns

  to reduce the amount of money you spend
• 6

   be on the horns of a dilemma

  to be in a situation in which you have to choose between two equally unpleasant or difficult situations

• ➔ blow your own trumpet/horn

   at blow1 (21)

   ➔ lock horns

  at lock1 (6)

   ➔ take the bull by the horns

   at bull1 (3)

Definition from the Longman Dictionary of Contemporary English
Advanced Learner's Dictionary.