How do you spell Riser

Available Definitions:
1)  n. - One who rises; as, an early riser.
2)  n. - The upright piece of a step, from tread to tread.
3)  n. - Any small upright face, as of a seat, platform, veranda, or the like.
4)  n. - A shaft excavated from below upward.
5)  n. - A feed head. See under Feed, n.