coaster
n. countablen. a small mat or object that you put under a glass or cup. It protects the surface of a table from heat or liquid marks.
n. a small piece of material, such as wood, plastic, or cork, placed under a drinking vessel to protect the surface of furniture. In computing contexts, it refers to a useless or corrupted optical disc.
Please use a coaster so you don't mark the wooden table.
She bought a set of marble coasters to match the new coffee table in the living room.
While the primary function of a coaster is utilitarian, many people collect them as souvenirs from bars and restaurants they have visited during their travels.
From coast (“edge of the land where it meets an ocean, sea, gulf, bay, or large lake”) + -er (suffix forming agent nouns). Coast is derived from Middle English coste (“rib; side of the body, flank; side of a building; face of a solid figure; coast, shore; bay, gulf; sea; concavity, hollow; boundary, limit; land; country; district, province, region; locality, place; division of the heavens; compass direction; direction; location with reference to direction, side”) [and other forms], from Old French coste (“rib; side of an object; coast”) (modern French côte (“rib; coast; hill, slope”)), from Latin costa (“rib; side, wall”).
From coast (“to glide along without adding energy; to make a minimal effort; to slide downhill (especially, to slide on a sled upon snow or ice)”) + -er (suffix forming agent nouns). Coast is derived from Middle English costeien (“to travel along a border or coast; to go alongside (something), skirt; to accompany, follow; to travel across, traverse; to be adjacent to, to border;”) [and other forms], from Anglo-Norman [Term?], Old French costoier (“to be at the side of”) [and other forms] (modern French côtoyer (“to pass alongside; (figuratively) to rub shoulders”)), from Latin costicāre, from costa (“rib; side, wall”); see further at etymology 1. etymology 2 sense 2.1 (“small stand or tray”) is from the fact that the object and the decanter or wine bottle on it “coast” or travel around a tabletop from person to person. etymology 2 sense 2.2.2 (“useless compact disc or DVD”) refers to the fact that the object is only useful as a drink coaster. etymology 2 sense 2.5 (“minibus”) is a genericized trademark from Toyota Coaster. Compare Spanish coaster / cúster.