deck

noun [具体名词]甲板，舱面；（船或公共汽车的）层；<美>一副牌；（屋后供休息的）木制平台；（唱机的）盘装置，（音响系统的）走带机构

A deck on a vehicle such as a bus or ship is a lower or upper area of it.
(公共汽车或船的) 层 •  ...a luxury liner with five passenger decks.  …一艘有5层舱位楼层的豪华游轮。