damper

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. One that deadens, restrains, or depresses: Rain put a damper on our picnic plans.
2. n. An adjustable plate, as in the flue of a furnace or stove, for controlling the draft.
3. n. Music A device in various keyboard instruments for deadening the vibrations of the strings.
4. n. Music A mute for various brass instruments.
5. n. A device that eliminates or progressively diminishes vibrations or oscillations, as of a magnetic needle.

Century Dictionary and Cyclopedia

1. n. One who or that which damps. A mechanical device for checking action in something with which it is connected.
2. n. A kind of unfermented bread, made of flour and water, and generally baked on a stone.

Wiktionary

1. n. Something that damps or checks:
2. n. Bread made from a basic recipe of flour, water, milk, and salt, but without yeast.
3. adj. comparative form of damp: more damp

GNU Webster's 1913

1. n. A valve or movable plate in the flue or other part of a stove, furnace, etc., used to check or regulate the draught of air.
2. n. A contrivance, as in a pianoforte, to deaden vibrations; or, as in other pieces of mechanism, to check some action at a particular time.

WordNet 3.0

1. n. a device that decreases the amplitude of electronic, mechanical, acoustical, or aerodynamic oscillations
2. n. a movable iron plate that regulates the draft in a stove or chimney or furnace
3. n. a depressing restraint