Definify.com
Webster 1913 Edition
damper
damp′er
(dăm′pẽr)
, Noun.
 That which damps or checks; 
as: 
(a) 
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. 
(b) 
A contrivance, as in a pianoforte, to deaden vibrations; or, as in other pieces of mechanism, to check some action at a particular time. 
Nor did Sabrina’s presence seem to act as any 
– damper 
at the modest little festivities. W. Black.
Damp′ish-ly
, adv.
 Damp′ish-ness
, Noun.
Webster 1828 Edition
Damper
DAMP'ER
,Noun.
 2.
  A part of a piano-forte, by which the sound is deadened.Definition 2025
damper
damper
English
Noun
damper (plural dampers)

Tuned mass oscillations damper.
-  Something that damps or checks:
- 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.
 - A contrivance (sordine), as in a pianoforte, to deaden vibrations; or, as in other pieces of mechanism, to check some action at a particular time.
 -  Something that kills the mood.
-  (Can we date this quote?) W. Black
- Nor did Sabrina′s presence seem to act as any damper at the modest little festivities.
 
 
 -  (Can we date this quote?) W. Black
 - A device that decreases the oscillations of a system.
 
 -  (chiefly Australia) Bread made from a basic recipe of flour, water, milk, and salt, but without yeast.
-  1827, Peter Cunningham, Two Years in New South Wales, ii.190, quoted in G. A. Wilkes, A Dictionary of Australian Colloquialisms, 1978, ISBN 0-424-00034-2,
- The farm-men usually bake their flour into flat cakes, which they call dampers, and cook these in the ashes.
 
 -  Rudyard Kipling, His Gift
- […] an open wood fire, from the ashes of which he drew forth (talking all the while) wonderful hot cakes called "dampers" […]
 
 
 -  1827, Peter Cunningham, Two Years in New South Wales, ii.190, quoted in G. A. Wilkes, A Dictionary of Australian Colloquialisms, 1978, ISBN 0-424-00034-2,
 
Translations
valve or movable plate used to regulate flow of air
contrivance to deaden vibrations
  | 
thing that kills the mood
  | 
Adjective
damper