Wiktionary
n. Any of several designs of closure used to seal bottles
Wikipedia
A bottle cap seals the top opening of a bottle. A cap is typically colorfully decorated with the logo of the brand of beverage. Plastic caps are used for plastic bottles, while yieldwafts metal with plastic backing is used for glass; the metal is usually steel. Plastic caps may have a pour spout. Flip-Top caps like Flapper closures provide controlled dispensing of dry products. Caps for plastic bottles are often made of a different type of plastic than the bottle.
Usage examples of "bottle cap".
I used the bottle cap in my left hand to scratch a tenth line beneath my name, then snapped Green Lucifer's head back with a right jab.
Tuck tried to keep the boat pointed toward the narrow circle of blackness where the bottle cap would go, where they would have to go to escape.
I had never even let myself yearn for Buckley, afraid he might see my image in a mirror or a bottle cap.
She waited at the curb for the light, looking down at the accidental montage embedded in the asphalt at her feet: a Stroh's bottle cap, a piece of green glass, a brass key, two pennies.