1.AdjectiveLocated on a higher floor or level of a building.
"We rent out the upstairs bedroom to a student."
2.AdjectivePertaining to a pitched ball that is high, and usually outside the strike zone.
"That fastball was upstairs for a ball."
3.AdverbUp the stairs; on or to a higher floor or level.
"I’ll take my shoes and put them away the next time I go upstairs.; I hate the people who live upstairs, and I especially hate their piano.; The woman upstairs told the people outside to stop reveling."
4.AdverbIn 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."
5.AdverbIn heaven, especially with regard to where a deity might be found.