coaster
/ˈkəustə(r); `kostɚ/ n
1
(a) small mat put under a drinking-glass to protect a polished table, etc from drips 杯垫.
(b) small tray for holding a decanter, wine bottle, etc （放饮料瓶、 酒瓶等的）小托盘.
2 ship that sails from port to port along a coast （沿海岸各港口航行的）轮船.