radiator

Etymology

It is formed from English radiate + -or,^[2][3][4][5] an agent noun in Latin form.^[6] The verb radiate is from Latin radiō (“to beam, shine, gleam”), through its past participle radiātus, from radius (“beam of light; spoke of a wheel”).^[6]

Earliest recorded meaning

Something that gives off heat, light or another form of energy: 1811, in the Journal of Natural Philosophy.^[2][3] Etymonline dates the word to 1832, as anything that radiates.^[6]

Semantic evolution

The general sense of something that radiates was soon narrowed to a heating device.^[6] A metal enclosure or set of pipes through which hot water, steam or air circulates to warm a room is recorded from 1838, in a newspaper from Bangor, Maine;^[2] Etymonline finds the sense of a device passing heat from steam to a room by 1855.^[6] In radio a radiator was a transmitting aerial from 1897,^[2] and since 1900 the word named the bank of thin tubes that cools the water circulating round the cylinders of an internal-combustion engine;^[2] Etymonline dates this sense to 1899.^[6] In Australia and New Zealand a radiator is also an electric fire.^[7]

Timeline

• 1811 – something that radiates heat, light or other energy.^[2][3]
• 1838 – a device for heating a room by circulating hot water, steam or air.^[2] Etymonline dates this sense to 1855.^[6]
• 1897 – in radio, a transmitting aerial.^[2]
• 1900 – the cooling device of an internal-combustion engine.^[2] Etymonline dates it to 1899.^[6]

Meanings

Noun

1. A device for heating a room, made of pipes or a flat metal panel through which hot water or steam passes: They hung the wet socks on the radiator.^[7][2]
2. A device for cooling an internal-combustion engine, made of thin tubes in which the circulating water gives off its heat to the air.^[7][2]
3. Anything that gives off radiation, such as heat, light or sound.^[3][2]
4. (Australia and New Zealand) An electric heater.^[7]
5. In electronics, the part of an aerial that sends out the radio waves.^[7][2]

Related words

• radiate
• radiation
• radius
• ray
• radiant

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
4. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
5. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
6. ^ a b c d e f g h Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
7. ^ a b c d e Collins English Dictionary (2023), Glasgow: HarperCollins