riser

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. One who rises, especially from sleep: She is a late riser.
2. n. The vertical part of a stair step.
3. n. A platform, as for elevating a group of people above a crowd, often arranged with similar platforms in tiers.

Century Dictionary and Cyclopedia

1. n. One who or that which rises. Specifically— One who leaves his bed: generally with a qualifying word.
2. n. One who revolts; a rebel or rioter.
3. n. In angling, a fish considered with reference to its manner of rising.
4. n. In founding: An opening in a molding-flask into which the molten metal rises as the flask is filled; a head.
5. n. Same as feed-head, 2.
6. n. The vertical face of a stairstep. Also raiser and lift.
7. n. plural In printing, blocks of wood or metal upon which electrotype plates are mounted to raise them to the height of type. [Eng.]
8. n. A riser pipe; any pipe which conveys a supply of hot or cold water, steam, gas, etc., from the source of supply upward, as through a building to bathrooms, radiators, or gas-fixtures.
9. n. In bee-keeping, a portion of a hive inserted under another hive to make more room.
10. n. In electricity, a wire connecting the various floors of a building and serving for the transmission of currents for electric lighting or power.

Wiktionary

1. n. Someone or something which rises.
2. n. A platform or stand used to lift or elevate something.
3. n. The vertical part of a step on a staircase.
4. n. archery The main body of a bow.
5. n. A conduit or path between floors of a building for placement of telephone, networking, and other utility cables.
6. n. A Manx cat with an extremely short tail.

GNU Webster's 1913

1. n. One who rises.
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. (Mining) A shaft excavated from below upward.
5. n. (Founding) A feed head. See under Feed, n.

WordNet 3.0

1. n. a person who rises (especially from bed)
2. n. a vertical pipe in a building
3. n. structural member consisting of the vertical part of a stair or step