I recently read an article (which was interesting and I learned stuff and all) where they were talking about commodity prices per metric tonne, using the abbreviation "mt".
And just. Guh! An abbreviated metric unit (which the tonne really isn't, the whole point of a metric system is we should be calling it a megagram, but anyway), that starts with a lowercase m. We know what that means, it should be 1/1000 of whatever a t is.