Forum Overview :: Dr. Dan Buroker, M.D.'s Team Fortress 2 :: Let's find out what it means

[quote name="Ray of Light"]Oops! Million! [quote]MM an abbreviation for one million, seen in a few traditional units such as those listed below. The abbreviation is meant to indicate one thousand thousand, M being the Roman numeral 1000. However, it actually means 2000, not one million, in Roman numeration. Since the single letter M is now used commonly for one million, the use of the double MM is confusing and strongly discouraged.[/quote] I'm not sure why they discourage its use just because it's confusing; that was a big part of the appeal to me. While uppercase is more conventional, luckily for me roman numerals mean the same thing in either case. Not far below that is this crazy definition: [quote]m/m an abbreviation for "by mass," used in chemistry and pharmacology to describe the concentration of a substance in a mixture or solution. 2% m/m means that the mass of the substance is 2% of the total mass of the solution or mixture.[/quote][/quote]