Definition of "stair" []

• A series or flight of steps; a staircase. Often used in the plural. (noun)
• One of a flight of steps. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Do you know why in the Vatican museum the stair is a double helix?"
• "The small kitchen was at the top of the main stair case in Bruch House, in the section reserved for amenities like lifts, plumbing, and entrances."
• "Each stair is illuminated by a three beam spotlight and all the wires are intelligently hidden."