http://www.dictionary.com/browse/roar noun
8. a loud, deep cry or howl, as of an animal or a person: the roar of a lion.
9. a loud, confused, constant noise or sound; din; clamor: the roar of the surf; the roar of lively conversation from the crowded party.
10. a loud outburst: a roar of laughter; a roar of approval from the audience