boiler
B2Pronunciation
UK
- /bˈɔɪlə/
US
- /ˈbɔɪlər/
Meanings
Noun
a tank or appliance that heats water for a building's heating or hot-water system
a closed vessel that produces steam or heated water for industrial equipment or engines
Beyond the definition
A boiler isn’t just something you see in old steam locomotives. While it can be the heart of a locomotive, it is fundamentally a closed vessel built to heat water or other fluids, producing steam or hot water. In many homes, a boiler is the quiet engine of comfort, turning fuel or electricity into warmth that flows through radiators or underfloor pipes.
Historically, boilers were central to the Industrial Revolution, powering massive machinery and changing the scale of production. They remain essential today for generating electricity and for manufacturing and hospital sterilization processes that rely on controlled steam and heat. You may also hear the term "boiler room" in modern language, describing a high-pressure environment where stress and urgency are intense.
A boiler is a specialized pressure vessel designed to heat water, or sometimes other liquids, to create steam or hot water. This heated fluid is then circulated to provide warmth, support sterilization, or drive engines and turbines.
The iconic image of a boiler comes from the age of steam: huge metal systems powering trains and ships in the 19th century. Those early designs burned coal or wood to create high-pressure steam for pistons and mechanical motion. Modern boilers are much more efficient and can run on natural gas, oil, propane, biomass, or electricity.
In homes, a boiler often acts as the central hub of a heating system, sending hot water through pipes to radiators or floor loops. In industry, their role is broader: they generate high-pressure steam for power generation and for processing in factories and hospitals.
The term also appears in figurative language. "Boiler room" can mean a cramped, high-pressure workplace, and the image captures the same idea as a real boiler—great power held under pressure, demanding careful control.
Examples
- 1
Home heating
We had to replace the old boiler before winter.
- 2
Hot water
The boiler broke down, so we had no hot water this morning.
- 3
Safety inspection
A gas boiler should be checked once a year by a qualified engineer.
See also
Forms and spellings
2 forms open this card.
Main spelling
- boilernoun
Forms
- boilerspluralnoun