Here I am trying to "catch up" on threads in here during the middle of the night. . . . this whole "metric" load issue is painful for me to endure. . . . I can see nobody has a clue what they're talking about. Millsapa has appropriated a meaningful expression without understanding the meaning. Nobody else here seems to know the origins or meaning of the expression. I do. I have been all over the place in my time, always observant, always critical, always thinking about it all. It's from the vocabulary of the pidgin variety of English commonly spoken by forklift operators in warehouses. . . . well back when those guys used to speak English in the first place. . . .
"A ton" was a precedent expression. Something weighs "a ton" if it's heavy, usually very heavy. . . . . Another precedent expression was "????load" or for LDS folks who have peculiar expressions in the place of normal profanity, with more pointed terminology, "!!!!load" as Millsape encrypted it. In the never-ending quest for particular emphasis in language which the ignorant are subject to in lieu of higher forms of expression, these two precedents have been combined by the forklift operators to create the progressive leap past the unutterable "ton !!!!load" through "metric ton !!!!load" all the way to the sublime "metric !!!!load". With the added emphasis commonly known to forklift operators that a metric ton is 1000kg or 2200 lbs while an Imperial ton is only 2000 lbs.
There's been a lot of water under the bridge in defining the ounce, but it appears to be a settling reality that the regular Avoirdupois ounce and pound are the only remnants of the Avoidupois system, with a modern established definition of apporximately 28.35 grams, or one sixteenth of a pound, which is 453.6 grams, while the troy ounce will likely continue to be used in precious metal trade, defined as 31.1 gram. The British have officially progressed from their Imperial system to the metric system, making it illegal to trade on the basis of the former system. We also have a separate definition for the fluid oz at around 30 grams or 30cc of fluid.
https://en.wikipedia.org/wiki/Ounce