/ Thesaurus / B Synonyms of british thermal unit Find synonyms for: Noun1. British thermal unit, BTU, B.Th.U., work unit, heat unit, energy unitusage: a unit of heat equal to the amount of heat required to raise one pound of water one degree Fahrenheit at one atmosphere pressure; equivalent to 251.997 caloriesWordNet 3.0 Copyright © 2006 by Princeton University. All rights reserved. Related Content Daily Word Quiz: entomology Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language