Ris"er (?), n.
1.
One who rises; as, an early riser.
2. Arch. (a)
The upright piece of a step, from tread to tread.
Hence: (b)
Any small upright face, as of a seat, platform, veranda, or the like.
3. Mining
A shaft excavated from below upward.
4. Founding
A feed head. See under Feed, n.
© Webster 1913.