BRITISH THERMAL UNIT(noun) Did you mean: Rhymes Definitions There is 1 meaning of the phrase British Thermal Unit. British Thermal Unit - as a noun 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 calories Synonyms (Exact Relations)b.th.u.btuWord Variations & RelationsStarts B Starts BR Starts BRI Starts BRIT Ends T Ends IT Ends NIT Ends UNIT Starts B & ends T Starts BR & ends T Starts B & ends IT A-Z Proximitiesbritches 15brith 10briths 11briticismbritish British Thermal Unit britisherbritishismbritonbrits 7britschka 20