From Old English stǣger 'staircase,' from Proto-Germanic *stīganą 'to climb.'
A set of steps leading from one floor or level to another inside or outside a building.
From Old English stǣger 'staircase,' from Proto-Germanic *staigriz, derived from the verb *stīganą 'to climb.' The singular stair originally meant the whole staircase; the plural became the normal form by the 14th century. Key roots: *steigh- (Proto-Indo-European: "to stride, step, rise").