in the upper story, on an upper floor, overhead, above, up the steps; see also upper.
the upper story, the penthouse, the sleeping apartments, the rooms above the ground floor; see attic, floor 2.
"upstairs." YourDictionary, n.d. Web. 19 August 2018. <http://thesaurus.yourdictionary.com/upstairs>.
upstairs. (n.d.). Retrieved August 19th, 2018, from http://thesaurus.yourdictionary.com/upstairs