damp ‧ er /ˈdæmpə $ -ər/ BrE AmE noun [countable]
1 . put a damper on something to make something less enjoyable, active, or great than it could have been:
A couple of knee injuries put a damper on his football career.
2 . a type of small metal door that is opened or closed in a ↑ stove or ↑ furnace , to control the air reaching the fire so that it burns more or less strongly
3 . a piece of equipment that stops a movement from being too strong
4 . a piece of equipment that stops a piano string from making a sound