Crown cap, also known as a bottle cap or twist-off cap, is a small but essential part of a beverage bottle. It seals the bottle and prevents the contents from spilling or losing carbonation. There are various synonyms for crown cap such as crimp cap, metal closure, screw cap, swing cap, and snap cap. These synonyms are used interchangeably depending on the type of cap and the industry it is used in. Crimp caps are mostly used in the pharmaceutical industry, while swing caps are commonly used in wine and beer bottles. Metal closure and screw cap are widely used in the food and beverage industry.