Stairs
Stairway
noun
The floor that makes up the steps are the stairs. Don't get this confused with the similar word 段階, which is the stairs making up the floors to a certain stage.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
階段で転んでひざから血が出てしまった。
I tripped over a stairway and my knee bled.
階段を上がったら、向かって右側の電車に乗って下さい。
When you go up the stairs, please take the train on the right.
こうしてみんな、一歩ずつ大人の階段を上がっていくんだよ。
This is how we all climb the stairs to adulthood, one step at a time.
充は、私が階段の掃除を手伝った事に礼を述べた。
Mitsuru thanked me for helping him clean the stairs.