Why is pork shoulder called Boston butt?

The term "Boston butt" for pork shoulder is believed to have originated in the 17th century when saloons in Boston began serving a dish made from the shoulder of the pig. The name "Boston butt" was most likely derived from the fact that the barrels used to store the meat were commonly called "butts." Over time, the term "Boston butt" became widely used to refer to the pork shoulder cut.