The informative series Today I Found Out reveals the most probably explanation for why a dollar is often called a “buck.” Host Simon Whistler explains the slang term most likely derives from the practice of trading deer and other animal skins as currency before the America dollar was established in 1792.
As with many etymologies, the exact root of this word is difficult to say with one hundred percent certainty. However, the leading theory is extremely plausible and backed up by a fair bit of documented evidence. Specifically, it is thought that a dollar is called a “buck” thanks to deer.
