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heater

American  
[hee-ter] / ˈhi tər /

noun

  1. any of various apparatus for heating, especially for heating water or the air in a room.

  2. Electronics. the element of a vacuum tube that carries the current for heating a cathode.

  3. Slang. a pistol, revolver, or other firearm.

heater British  
/ ˈhiːtə /

noun

  1. any device for supplying heat, such as a hot-air blower, radiator, convector, etc

  2. slang a pistol

  3. electronics a conductor carrying a current that indirectly heats the cathode in some types of valve

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

Etymology

Origin of heater

First recorded in 1490–1500; heat + -er 1

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The team spokesman said rodent activity was not found in any food preparation areas, that it occurred underneath a storage rack and next to a water heater.

From Los Angeles Times • Apr. 28, 2026

Now the family use a small immersion heater for hot water, which usually is enough for a couple of showers.

From BBC • Apr. 22, 2026

An all-electric, energy-efficient alternative to gas-burning furnaces, heat pumps are widely seen as the climate-friendly home heater of choice.

From Los Angeles Times • Mar. 1, 2026

I pondered ways to scale back on energy usage, by swapping the space heater for 60-watt electric blankets, for instance.

From The Wall Street Journal • Feb. 1, 2026

She sets it carefully on top of the heater while I grab the towel we use for bathing and spread it on the bed.

From "The Light in Hidden Places" by Sharon Cameron

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.