Collocations for stair - noun

steep
wide
narrow
rickety
spiral
main
back
basement
My kids sat on the basement stairs.

marble, metal, stone, wooden

flight
We went up three flights of stairs.

ascend, climb, mount
go up, run up, etc.
descend
go down, run down, etc.
take, use
Take the back stairs.

go down to sth, go up to sth, lead to sth
creak
The stairs creaked as I went down.

rod (esp. BrE)
The carpet was held in place by brass stair rods.

rail (AmE)
gate (esp. BrE)

under the stairs
a cupboard under the stairs (BrE)
a closet under the stairs (AmE)

stairs down to, stairs to, stairs up to
the stairs to the third floor

the bottom of the stairs, the foot of the stairs, the head of the stairs, the top of the stairs
take the stairs two, etc. at a time
He rushed up to the bedroom, taking the stairs two at a time.

top
bottom

on a/the stair
He sat waiting on the bottom stair.