stopper
n. countable B2 Upper Intermediate US //ˈstɑpɝ// UK //stˈɒpɐ// stop·per
n. a small object, like a cork or a plug, that you put into the top of a bottle or jar to close it. It keeps the liquid inside and prevents air from getting in.
n. an object, such as a plug or bung, designed to seal the opening of a container. Often made of glass, cork, or rubber to ensure an airtight or watertight fit.
She put the glass stopper back in the perfume bottle.
After pouring the wine, he replaced the decorative stopper to keep the remaining liquid fresh.
The chemist carefully inserted the ground-glass stopper into the flask to prevent the volatile reagents from evaporating during the overnight reaction.
From stop + -er.
Usage
Commonly refers to the removable closure of a bottle, distinct from a screw-on cap.