Pronunciation: (kō'stur),[key] —n. 1. a person or thing that coasts.
2. a small dish, tray, or mat, esp. for placing under a glass to protect a table from moisture.
3. a ship engaged in coastwise trade.
4. a sled for coasting.
5. a tray for holding a decanter to be passed around a dining table.
6. See roller coaster.