n.1 each of a set of fixed indoor steps (on the top stair but one).
2 (usu. in pl.) a set of indoor steps (passed him on the stairs; down a winding stair).
3 (in pl.) a landing-stage.
Phrases and idioms:
stair-rod a rod for securing a carpet in the angle between two steps.
Etymology: OE st{aelig}ger f. Gmc