coaster
noun [ C ] uk/ˈkəʊ.stər/ us/ˈkoʊ.stɚ/
(OBJECT)
杯垫
a small piece of wood, plastic, or other material that you put a glass or cup on to protect a surface from heat or liquid
(BOAT)
（航行于沿海港口间的）船只
a ship that sails between ports along a coast