close-fitting cap
nounUK /ˌkləʊs ˈfɪtɪŋ kæp/
US /ˌkloʊs ˈfɪtɪŋ kæp/
A close-fitting cap is a small hat that fits tightly on your head.
The swimmer wore a close-fitting cap to keep her hair dry.
OTHER MEANINGS
2. A tight cap worn for sports or swimming to reduce drag.
He pulled on a close-fitting cap before diving into the pool.
3. A snug head covering worn under a helmet for warmth.
She wore a close-fitting cap beneath her bike helmet on cold mornings.
4. A small tight hat worn as part of a uniform or costume.
The nurse's close-fitting cap stayed neat all through her shift.