Definition of therm in English:



  • A unit of heat, especially as the former statutory unit of gas supplied in the UK equivalent to 100,000 British thermal units or 1.055 × 10⁸ joules.

    • ‘They would be paying 40p a therm for wholesale gas compared to historic prices of 20p - 22p.’
    • ‘That level is more than double last January's average price of 28.8 pence per therm.’
    • ‘The dash for gas looked like a smart idea when it cost less than 20p a therm and developers were falling over themselves to build the next generation of low-cost stations.’
    • ‘It had to suspend production for a week in February when spot prices for UK natural gas reached £1.16 a therm.’
    • ‘UK gas prices stood at 12p a therm at the beginning of 2000 but now stand in excess of 55p a therm - and have been as high as 75p recently.’
    • ‘The wholesale price of gas in Britain has gone from 11p per therm in 1999 to 44p per therm in 2005.’
    • ‘Luckily, there are plenty of units for energy, so it is probably best to just leave the calorie unit to the food people, and use joules or Kilowatt hours or therms or ergs for energy calculations unrelated to human nutrition.’
    • ‘Gas for delivery on Monday traded at £1.10 a therm on Friday - up 40p on the day - taking prices to the highest level since December 1997.’
    • ‘At present, natural gas can cost anywhere between 18p and 25p a therm for industrial users while their contract terms are based on 12p a therm for a period of 10 years.’
    • ‘Across all sites measured by the Energy Information Centre, the ‘delivered rate’ for gas rose 72% to 69p a therm.’


1920s: from Greek thermē ‘heat’.