up the stairs; to or on an upper floor.

Informal . in the mind

to be a little weak upstairs.

to or at a higher level of authority

You may have to take the matter upstairs.

Military Slang . at or to a higher level in the air.

Also, upstair. of, pertaining to, or situated on an upper floor

an upstairs window; an upstairs apartment.

( usually used with a singular verb ) an upper story or stories; the part of a building or house that is above the ground floor

The upstairs of this house is entirely rented.

a higher command or level of authority

We can't take action till we have approval from upstairs.

kick upstairs, to promote (a person) to a higher position, usually having less authority

in order to be rid of him or her.