Definition from Wiktionary, the free dictionary
- (intransitive, UK) To become quieter
- As the lights dimmed the general noise quietened down.
- (intransitive, UK) To reduce intensity of an activity.
- Diplomacy can only begin when the violence quietens down.
- (transitive, UK) To make someone or something become quieter.
- The teacher did her best to quieten the children down.
- quiet down which is preferred usage in US.