From up + stair + -s



upstairs ‎(comparative further upstairs, superlative furthest upstairs)

  1. located higher up a building.
    They can sleep in the upstairs bedroom.
    • 1891, Thomas Hardy, Tess of the d’Urbervilles , chapter IV
      In a large bedroom upstairs, the window of which was thickly curtained with a great woollen shawl lately discarded by the landlady, Mrs Rolliver, were gathered on this evening nearly a dozen persons, all seeking beatitude; all old inhabitants of the nearer end of Marlott, and frequenters of this retreat.
  2. (baseball) a pitched ball that is high, and usually outside the strike zone
    That fastball was upstairs for a ball.



upstairs ‎(comparative further upstairs, superlative furthest upstairs)

  1. Up the stairs; on 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.
  2. (colloquial) In the brain.
    After Joe did a hula dance on the kitchen table, his friends wondered if he didn't have a lot going on upstairs.
  3. (colloquial) In heaven, or any other place where a deity might be found.