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• therm
  therm

  noun

  any of several units of heat, as one equivalent to 1000 large calories or 100,000 British thermal units.
• therm-
  therm-

  variant of thermo- before a vowel.
• -therm
  -therm

  variant of thermo- as final element in compound words.
• therm.
  therm.

  abbreviation

  thermometer.

therm

¹ American  

[thurm] / θɜrm /

Or therme

noun

Physics.

1. any of several units of heat, as one equivalent to 1000 large calories or 100,000 British thermal units.

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therm- ² American  

1. variant of thermo- before a vowel.

   thermesthesia.

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-therm ³ American  

1. variant of thermo- as final element in compound words.

   isotherm.

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therm. ⁴ American  

abbreviation

1. thermometer.

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therm British  

/ θɜːm /

noun

1. a unit of heat equal to 100 000 British thermal units. One therm is equal to 1.055 056 × 10 ⁸ joules

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Etymology

Origin of therm

First recorded in 1885–90, therm is from the Greek word thérmē heat

Example Sentences

The benchmark UK gas price was below 80p a therm before the Iran war began but was trading at around 157p by 19 March.

From BBC • Jun. 18, 2026

The level has been set at $71.40 per barrel for oil and £0.54 per therm for gas.

From BBC • Jun. 9, 2023

British gas for immediate delivery was up 85 pence to 450 pence per therm at 0940 GMT, while the day-ahead contract rose 119 pence to 480 p/therm.

From Reuters • Aug. 22, 2022

It is currently 8.3% higher at 426.9p per therm, not far from the all-time high of around 450p in December.

From The Guardian • Mar. 3, 2022

It is 251.9 times greater than the metric unit, therm or calorie, which is the amount of heat required to raise one gramme of water from 4 degrees to 5 degrees centigrade.

From The Story of Electricity by Munro, John