ClipArt ETC
Caps, or Closures, are used to seal the openings of bottles of many types. They can be small circular pieces of metal, usually steel, with plastic backings, and for plastic bottles a plastic cap is used instead.

Bottle Cap

Caps, or Closures, are used to seal the openings of bottles of many types. They can be small circular…

Bottle caps, or "closures", are used to seal the openings of bottles of many types.

Bottle Top

Bottle caps, or "closures", are used to seal the openings of bottles of many types.