From WordNet (r) 3.0 (2006):
roar
n 1: a deep prolonged loud noise [syn: boom, roar,
roaring, thunder]
2: a very loud utterance (like the sound of an animal); "his
bellow filled the hallway" [syn: bellow, bellowing,
holla, holler, hollering, hollo, holloa, roar,
roaring, yowl]
3: the sound made by a lion
v 1: make a loud noise, as of wind, water, or vehicles; "The
wind was howling in the trees"; "The water roared down the
chute" [syn: roar, howl]
2: utter words loudly and forcefully; "`Get out of here,' he
roared" [syn: thunder, roar]
3: emit long loud cries; "wail in self-pity"; "howl with sorrow"
[syn: howl, ululate, wail, roar, yawl, yaup]
4: act or proceed in a riotous, turbulent, or disorderly way;
"desperadoes from the hills regularly roared in to take over
the town"-R.A.Billington
5: make a loud noise, as of animal; "The bull bellowed" [syn:
bellow, roar]
6: laugh unrestrainedly and heartily [syn: roar, howl]