Collins English-English Dictionary

roar [rɔː]

1. 1. vb [mainly intr] (of lions and other animals) to utter characteristic loud growling cries

2. 2. vb [also tr] (of people) to utter (something) with a loud deep cry, as in anger or triumph

3. 3. vb to laugh in a loud hearty unrestrained manner

4. 4. vb (of horses) to breathe with laboured rasping sounds - See roaring

5. 5. vb (of the wind, waves, etc) to blow or break loudly and violently, as during a storm

6. 6. vb (of a fire) to burn fiercely with a roaring sound

7. 7. vb (of a machine, gun, etc) to operate or move with a loud harsh noise

8. 8. vt. [tr] to bring (oneself) into a certain condition by roaring

   to roar oneself hoarse

9. 9. n a loud deep cry, uttered by a person or crowd, esp in anger or triumph

10. 10. n a prolonged loud cry of certain animals, esp lions

11. 11. n any similar noise made by a fire, the wind, waves, artillery, an engine, etc

12. 12. n a loud unrestrained burst of laughter

13. 13. n See also roar up

14. 14. n [Etymology] Old English rarian; related to Old High German reren, Middle Dutch reren