Definition of boiler:
(n) :
An apparatus for heating circulating water or other heat transferring liquid.
(n) :
A steam boiler.
(n) :
A device consisting of a heat source and a tank for storing hot water, typically for space heating, domestic hot water etc., disregarding the source of heat.
(n) :
A kitchen vessel for steaming, boiling or heating food.
(n) :
A person who boils something.
(n) :
A tough old chicken only suitable for cooking by boiling.