You searched for: “british thermal unit”
British thermal unit, Btu (s) (noun), British thermal units; Btus (pl)
An imperial unit of heat, now replaced in the SI system by the joule: One British thermal unit is approximately 1,055 joules).

Burning one cubic foot of natural gas releases about 1,000 Btu of heat.

This entry is located in the following unit: Measurements and Mathematics Terms (page 3)
British Thermal Unit; BTU, Btu
The amount of heat required to raise the temperature of one pound of water one degree Fahrenheit; equal to 252 calories.
This entry is located in the following unit: Photovoltaic Conversion Efficiency Terms + (page 3)