quietcap
nounUK /ˈkwaɪət.kæp/
US /ˈkwaɪət.kæp/
A quietcap is a soft cap you wear to help keep things calm and quiet.
She put on her quietcap before reading in the library.
OTHER MEANINGS
2. A small lid or cover that makes a container open and close without noise.
The jar had a quietcap so it wouldn't clink at night.
3. A person who stays very calm and silent in busy places.
Tom was a quietcap during the whole trip.
4. A gentle ending that brings a noisy event to a peaceful close.
The fireworks show had a quietcap with soft lights.