boiler
noun /ˈbɔɪlə(r)/
  /ˈbɔɪlər/
 (also furnace especially in North American English)
- a container in which water is heated to provide hot water and heating in a building or to produce steam in an engine
- a central heating boiler
 - a gas boiler
 - a back boiler (= located behind a fire)
 
Extra ExamplesTopics Houses and homesc1- I've just heard the hot water boiler come on.
 - There was a gas boiler mounted on the far wall.
 - You might need to install a new boiler.