British thermal unit

noun

, Physics.

1. the amount of heat required to raise the temperature of 1 pound (0.4 kilogram) of water 1°F. : Btu, BTU, B.t.u., B.T.U., B.th.u.

British thermal unit

noun

1. a unit of heat in the fps system equal to the quantity of heat required to raise the temperature of 1 pound of water by 1°F. 1 British thermal unit is equivalent to 1055.06 joules or 251.997 calories AbbrevsbtuBThU

British thermal unit

/ brĭt′ĭsh /

1. A unit used mainly to measure heat but also applied to other forms of energy. One British thermal unit is equal to the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit, or 251.997 calories.

British thermal unit

1. A unit for measuring heat . One Btu raises the temperature of one pound of water one degree Fahrenheit (see also Fahrenheit ).

Word History and Origins

Origin of British thermal unit¹

First recorded in 1875–80