Where did the slang term “greenbacks” come from and what does it mean?

This slang word “greenbacks” for Union money came from the mouths of American Civil War soldiers—or, as they called each other, graybacks and yankees.

A slue of slang terms originated from these guys, many of them still in use today.

Take for instance breadbasket (stomach), Chief cook and bottle washer (someone in charge who can multitask well), fit to be tied (madder’n a hornet!), horse sense (common sense), snug as a bug (very comfortable), skedaddle (run along), blowhard (someone who boasts), fit as a fiddle (healthy and in shape), uppity (conceited), goobers (peanuts), and hunkey dorey (good).