stair,stairs,staircase,step,stairway 这五个词都有楼梯的意思,有什么不同吗?

stair,n.
1.(阶梯等的)一级,梯级
2.[用复数,用作单数或复数]阶梯,楼梯
3.[用复数]【船舶学】浮动平台
4.阶梯,途径
stair [stεə] n.
support consisting of a place to rest the foot while ascending or descending a stairway
stairs——是stair的复数形式.
staircase ['stεəkeis] n.楼梯；楼梯间【即可指“楼梯”,还可指“设置楼梯的房间部分”】
a way of access (upward and downward) consisting of a set of steps
step 【重点强调“台阶”,而且,单复数意义不同.】 梯级,台阶；踏板.[用复数]一段楼梯,一段台阶
support consisting of a place to rest the foot while ascending or descending a stairway
stairway n.【建筑专业用词】 阶梯,楼梯
a way of access (upward and downward) consisting of a set of steps
当然,指代“台阶,阶梯”时,stair与step一般可互换.