우르르

1. in crowds; rushingly
A word describing people, animals, etc., moving at once or crowding into a place.

2. boiling up
A word describing the sound or motion of liquid boiling or overflowing suddenly.

3. with a crash; with a rumbling
A word describing the sound or motion of a heap of things crumbling or tumbling suddenly.

4. with a rumbling
A word imitating the sound of water falling from a waterfall or the sound of thundering.