stair
/steə(r)/noun
(一般作stairs)
1- a set of steps leading from one floor of a building to another, typically inside the building楼梯：
he came up the stairs.
他走上楼来。
1.1
- single step in such a set梯级：
the bottom stair.
最下面一级楼梯。
词源
Old English stæger, of Germanic origin: related to Dutch steiger 'scaffolding', from a base meaning 'climb'.