Beverage coaster

A beverage coaster is a little piece of material, like paper or cork or even stone, that you put under your cup or glass to protect the surface underneath. It's like a little mat for your cup to rest on. When you put your cup down on the coaster instead of directly on a table or desk, it helps keep your drink from making marks or rings on the surface, and it also helps keep your drink from spilling if you accidentally knock it over. So coaster is like a little helper for your cup or glass to keep it steady and safe, as well as to keep the surface under it clean and unmarked.