ris·er /ˈraɪzɚ/
  起床者,叛徒,起義者,豎板
  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.
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  riser
       n 1: a person who rises (especially from bed); "he's usually a
            late riser"
       2: a vertical pipe in a building [syn: riser pipe, riser
          pipeline, riser main]
       3: structural member consisting of the vertical part of a stair
          or step