boiler

noun

boil·​er ˈbȯi-lər 

1

: one that boils

2

a

: a vessel used for boiling

b

: the part of a steam generator in which water is converted into steam and which consists usually of metal shells and tubes

c

: a tank in which water is heated or hot water is stored

d

chiefly British : furnace

Examples of boiler in a Sentence

Recent Examples on the Web

These include blending hydrogen with natural gas for use in pipelines, powering heavy-duty trucks, and using hydrogen in industrial boilers. —Sujita Sinha, Interesting Engineering, 27 Apr. 2026

With a firm hold, the landlady showed me how to switch on the boiler and wait for ten minutes until the hot water came. —Literary Hub, 27 Apr. 2026

Valerii, who worked in the plant’s boiler house, and hoped to one day be promoted to one of its reactor shops, was taken by Nataliia’s gentle beauty, practicality, and work ethic. —Lizzie Johnson, New Yorker, 25 Apr. 2026

Geothermal is four times more efficient than a boiler or furnace and twice as efficient as an air-source heat pump. —Lew Sichelman, Miami Herald, 23 Apr. 2026

Word History

First Known Use

circa 1540, in the meaning defined at sense 1

Phrases Containing boiler

• boiler room
• double boiler
• steam boiler

Rhymes for boiler

• broiler
• oiler
• spoiler
• toiler
• reboiler

Kids Definition

boiler

noun

boil·​er ˈbȯi-lər 

1

: a container in which something is boiled

2

: a strong metal container used in making steam

3

: a tank in which water is heated or hot water is stored