What is Roar ?
Roar is (noun) a loud noise, e.g. of shouting or of an engine The roar of the jet engines made it impossible for me to hear what she said. You could hear the roar of the crowd at the football match several miles away. (verb) to make a loud noise He roared with laughter at the film. The lion roared and then attacked.
source: Easier English, Student Dictionary Upper Intermediate Level