stair

flight

The apartment building had four flights of stairs and no elevator.

take, use

She used the stairs carefully because her leg was still healing from the accident.

rod

The metal stair rod keeps the runner from slipping on the wooden steps.

under the ~

My cat likes to hide under the stairs when there's a thunderstorm.

~ (down/up) to

I climbed the stairs up to the attic to find my old boxes.

the bottom/foot/head/top of the stairs, take the stairs two, etc. at a time

She waited at the bottom of the stairs for her daughter to come down.

creak

The old wooden stairs creaked loudly whenever my grandmother walked up to her bedroom.

on/the a ~

The cat likes to nap on the middle stair of our house.