What is "up stairs"

Stair \Stair\ (st[^a]r), n. [OE. steir, steyer, AS. st[=ae]ger, from st[imac]gan to ascend, rise. [root]164. See Sty to ascend.]

1. One step of a series for ascending or descending to a different level; -- commonly applied to those within a building.

2. A series of steps, as for passing from one story of a house to another; -- commonly used in the plural; but originally used in the singular only. ``I a winding stair found.''
   --Chaucer's Dream.

   Below stairs, in the basement or lower part of a house, where the servants are.

   Flight of stairs, the stairs which make the whole ascent of a story.

   Pair of stairs, a set or flight of stairs. -- pair, in this phrase, having its old meaning of a set. See Pair, n., 1.

   Run of stairs (Arch.), a single set of stairs, or section of a stairway, from one platform to the next.

   Stair rod, a rod, usually of metal, for holding a stair carpet to its place.

   Up stairs. See Upstairs in the Vocabulary.