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ladder
stairs
going to several places in succession (e.g. barhopping)
「梯」 has another reading with different meanings.
屋根の修理のためにはしごをかけた。
I set up a ladder to repair the roof.
はしごを使って高い棚の上の箱を取った。
I used a ladder to get the box from the high shelf.
古いはしごは危ないので新しいものに替えた。
The old ladder was unsafe, so I replaced it with a new one.