Coaster meaning : Agent noun of coast: one who coasts. Something that coasts, such as a sled or toboggan. A merchant vessel that stays in coastal waters. A sailor who travels only in coastal waters. A person who originates from or inhabits a coastal area. A small piece of material used to protect the surface of a table, upon which one places cups or mugs. A small tray on wheels, used to pass something around a table. A worthless compact disc or DVD, such as one that was burned incorrectly. A rollercoaster. (Lake Superior) A coaster trout (brook trout, Salvelinus fontinalis) A prostitute, especially a white woman, plying her trade in Chinese port towns.