boiler: Meaning and Definition of

boil•er

1. a closed vessel or arrangement of vessels and tubes, together with a furnace or other heat source, in which steam or other vapor is generated from water to drive turbines or engines, supply heat, process certain materials, etc. Cf. fire-tube boiler, water-tube boiler.
2. a vessel, as a kettle, for boiling or heating.
3. a large tub in which laundry is boiled or sterilized.
4. a tank in which water is heated and stored, as for supplying hot water.