1. To make a low heavy, continuous sound or series of sounds: Polly and Todd could hear the thunder which was rumbling in the distance before the rain started to fall.
2. To move along with a low, heavy continuous sound: The trains rumble through town at least twice every day.
3. To fight; especially, in the street: The gangs were rumbling in the alley earlier today.
4. To continue for a long time: The political debate rumbled on for days during the TV news and special radio and TV discussions.

1. A low, heavy, continuous sound or series of sounds: The rumbling of the thunder last night frightened Alan's cat and disturbed its sleep for quite awhile.
2. Written or spoken comments showing that people are unhappy about something: There have been several rumblings of revolutionary demonstrations in many Middle East countries.