stair 
/ˈsteɚ/ noun
plural stairs /ˈsteɚ/ noun 1 stairs [plural] : a series of steps that go from one level or floor to another
▪ She ran down the stairs. ▪ He waited at the foot/bottom of the stairs. ▪ She slipped and fell down the stairs. ▪ The stairs lead to the roof. ▪ We had to climb another flight/set of stairs to get to the roof. 2 [count] : one of the steps in a set of stairs
▪ a squeaky stair ▪ He tripped on the bottom stair and almost fell. 3 [singular] literary : staircase
▪ climbing the stair
▪ She ran down the stairs. ▪ He waited at the foot/bottom of the stairs. ▪ She slipped and fell down the stairs. ▪ The stairs lead to the roof. ▪ We had to climb another flight/set of stairs to get to the roof.
▪ a squeaky stair ▪ He tripped on the bottom stair and almost fell.
▪ climbing the stair
