sealingcap
nounUK /ˈsiːlɪŋ kæp/
US /ˈsiːlɪŋ kæp/
A sealing cap is a small lid that closes a bottle or jar tightly so nothing leaks out.
She screwed the sealing cap back onto the bottle of juice.
OTHER MEANINGS
2. A protective cover that keeps dirt and water out of a pipe or tube.
The plumber fitted a sealing cap on the end of the pipe.
3. A cap worn to keep something airtight during storage.
Put the sealing cap on the paint can so it does not dry out.
4. A small part that closes a container so it can be carried without spilling.
The sealing cap on his water bottle never leaks in his bag.