Definitions of roar:

• noun:   the sound made by a lion
• noun:   a deep prolonged loud noise
• noun:   a very loud utterance (like the sound of an animal)
• verb:   laugh unrestrainedly and heartily
• verb:   make a loud noise, as of wind, water, or vehicles

  Example: "The water roared down the chute"

• verb:   act or proceed in a riotous, turbulent, or disorderly way

  Example: "Desperadoes from the hills regularly roared in to take over the town-R.A.Billington"

• verb:   utter words loudly and forcefully

  Example: "`Get out of here,' he roared"

• verb:   make a loud noise, as of animal
• verb:   emit long loud cries