heater

heater — noun

1. A machine or piece of equipment that warms a room, building, or the water supply

1.nounB1
Definition

A machine or piece of equipment that warms a room, building, or the water supply inside a home or office.

Example

The old electric heater in the living room started making a strange noise last night.

compound noun: electric heater

Tuan turned on the water heater and waited for the shower to warm up.

compound noun: water heater

Common collocations
  • electric heater
  • gas heater
  • water heater
  • space heater
  • portable heater
  • turn on the heater
  • turn off the heater
  • heater broke down
Synonyms
  • radiator

    a specific type of heater that uses hot water or steam and is usually fixed to a wall

  • furnace

    a large heater that warms an entire building, often using gas or oil; more typical of larger systems in colder climates

  • space heater

    a small portable heater used to warm a single room, often electric

Antonyms

Usage Note

Also commonly appears as part of compound nouns such as 'water heater', 'space heater', 'gas heater', and 'electric heater'.

Common Mistakes

I need to fix the heating because it's not working.
I need to fix the heater because it's not working.
'heating' refers to the system; 'heater' is the physical device.
The heater boiled the water for tea.
The kettle boiled the water for tea.
'heater' warms a room or water supply; a 'kettle' boils water for drinking.

2. A baseball pitch thrown at very high speed, especially a fastball; a term used b

2.nounB2
Definition

A baseball pitch thrown at very high speed, especially a fastball; a term used by players, commentators, and fans.

Example

The pitcher threw a 98-mile-per-hour heater that the batter swung at too late.

collocation: throw a heater

With two strikes against him, the batter braced himself for a high heater from Gabriel.

modifier: high heater

Common collocations
  • throw a heater
  • blazing heater
  • high heater
  • heater down the middle
  • heater at the knees
Synonyms
  • fastball

    the standard term; 'heater' is a more colourful, informal synonym

  • fast one

    informal; 'he threw him a fast one' can also mean a trick or surprise in general speech

  • hummer

    a very informal, less common slang synonym

Antonyms
  • changeup

    a slow pitch designed to look like a fastball, meant to throw off the batter's timing

Usage Note

Used almost exclusively in baseball contexts. The term is informal and appears most often in sports commentary and player interviews rather than in official rules or statistics.

Common Mistakes

The tennis player served a heater.
The baseball pitcher threw a heater.
'heater' as a term for a fastball is only used in baseball, not other sports.
The heater in the kitchen is on.' (intending baseball sense).
The pitcher threw a heater to strike him out.
without a baseball context, readers will assume the heating-device sense.

Word family

Synonym discussion

Sense: noun/1

All four words describe devices that produce warmth, but they differ in scope and typical use. A 'radiator' is a fixed unit, often metal, that releases heat from hot water or steam circulating through a building's central system — you find them against walls in older homes. A 'furnace' is a large appliance that heats air for an entire building, usually powered by gas or oil and located in a basement or utility closet. A 'space heater' is small, portable, and electric, designed to warm just one room. A 'boiler' heats water for radiators or taps and is part of a central heating system, not a room-level device. For everyday use: 'Should I turn on the space heater in the study?' uses the portable sense, while 'The furnace kicked on because it was freezing outside' refers to whole-house heating.

radiator ↗furnace ↗space heaterboiler

Common collocations

Nouns

  • gas heater
  • electric heater
  • water heater
  • space heater
  • portable heater
  • ceramic heater
  • fan heater
  • infrared heater

Phrases

  • turn on the heater
  • turn off the heater
  • fix the heater
  • replace the heater
  • the heater broke down

Etymology

Old EnglishEnglish

Formed in English from the verb 'heat' (from Old English 'hǣtu', meaning hotness or warmth) plus the agent suffix '-er', which marks it as a device that performs the action. The baseball slang sense for a fastball appeared in early 20th-century American English, likening the speed and force of the pitch to something hot or burning.