An upper storey.
Located on a higher floor or level of a building.
They can sleep in the upstairs bedroom.
Pertaining to a pitched ball that is high, and usually outside the strike zone.
That fastball was upstairs for a ball.
Up the stairs; on a higher floor or level.
I hate the people who live upstairs, and I especially hate their piano.
In the brain or mind.
After Joe did a hula dance on the kitchen table, his friends wondered if he didn’t have a lot going on upstairs.
In heaven, especially with regard to where a deity might be found.