What does the word upstairs mean?

Usage examples for upstairs

  1. Will you come with me upstairs? – News from the Duchy by Sir Arthur Thomas Quiller-Couch
  2. I don't understand what is going on upstairs; I want to ask you something. – The New Magdalen by Wilkie Collins
  3. I told her to go upstairs. – Walter Sherwood's Probation by Horatio Alger