Coaster can refer to:

• A small piece of material, usually composed of wood or of cardboard, used to prevent a drink and its container from contacting a surface, such as a table, and leaving marks from drips or condensation. See beermat.
• Roller coaster
• Coastal trading vessel
• San Diego Coaster (commuter rail service)
• A recordable optical disc (e.g. CD-R, DVD-R) which has not been recorded properly, and is therefore useless as a data storage medium; by implication its only use is as a drinks coaster
• A person associated with a certain coast. In New Zealand, specifically, coaster refers to a person from the West Coast of the South Island of New Zealand.
• A member of The Coasters, an American doo-wop band.

Bierdeckel | Coaster | sous-bock