quieten down

quieten down (third-person singular simple present quietens down, present participle quietening down, simple past and past participle quietened down)

1. (intransitive, Britain) To become quieter.

   As the lights dimmed the audience quietened down.

2. (intransitive, Britain) To reduce intensity of an activity.

   Diplomacy can only begin when the violence quietens down.

3. (transitive, Britain) To make someone or something become quieter.

   The teacher did her best to quieten the children down.

• quiet down (preferred in US)