Home › Words › M › mmbtummbtummbtu means one million BTUs.EtymologyReplaced the earlier MBtu (one thousand BTUs) as the 'M' could be misinterpreted as the SI prefix mega- (one million) or milli- (one thousandth)nounone million BTUsDefinitions & examples from Wiktionary (CC BY-SA 3.0).Words closest in meaningBy meaning, not spelling — each word's AI semantic fingerprint, nearest first.tcf 59% match — thousand cubic feet vs mmbtu →megaunit 56% match — A unit equal to one million of another unit. vs mmbtu →megabuck 55% match — A million dollars. vs mmbtu →megabar 54% match — A unit of pressure equal to one million bars vs mmbtu →multimillions 51% match — Multiple millions. vs mmbtu →megawattage 50% match — An amount of power expressed in megawatts. vs mmbtu →gigabarrel 50% match — A unit of volume equal to a thousand million barrels. vs mmbtu →mbps 49% match — megabit per second, a measure of data transfer rate vs mmbtu →