British thermal unit

noun

Definition of British thermal unit 

: the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit at a specified temperature (such as 39°F)

Did You Know?

Despite its name, the British thermal unit, or BTU, may be more widely used in North America than in Britain. Air conditioners, furnaces, and stoves are generally rated by BTUs. (Though "BTUs" is often short for "BTUs per hour;" in air-conditioner ratings, for instance, "BTUs" really means "BTUs of cooling capacity per hour".) Fuels such as natural gas and propane are also compared using BTUs. The BTU first appeared in 1876 and isn't part of the metric system--the metric unit of energy is the much smaller joule--so it isn't much used by scientists, but its practicality keeps it popular for consumer goods and fuels. A better-known heat unit is the calorie; a BTU is equal to about 252 calories. (Since the familiar food calorie is actually a kilocalorie, a BTU equals only about a quarter of a food calorie.)

First Known Use of British thermal unit

1865, in the meaning defined above

Keep scrolling for more

Learn More about British thermal unit

Share British thermal unit

Statistics for British thermal unit

Look-up Popularity

Time Traveler for British thermal unit

The first known use of British thermal unit was in 1865

See more words from the same year

Keep scrolling for more

More Definitions for British thermal unit

British thermal unit

noun

Medical Definition of British thermal unit 

: the quantity of heat required to raise the temperature of one pound of water one degree Fahrenheit at a specified temperature (as 39°F) abbreviation Btu

Comments on British thermal unit

What made you want to look up British thermal unit? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

alleviating pain or harshness

Get Word of the Day daily email!

Test Your Vocabulary

Musical Words Quiz

  • gramophone
  • Which word describes a musical performance marked by the absence of instrumental accompaniment?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Add Diction

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!