The phrase Rust Belt referred to the American industrial heartland far before its machines started actually rusting, first being used in 1869. Use back then was pretty scarce, however, and the term only got popular because of 1984 presidential candidate, who said in a speech that "Reagan's policies are turning our industrial Midwest into a rust bowl". Then the media adopted the toponym, tweaking it slightly to follow the model of the 1969 coinage Sun Belt (which referred to the southern US). Eventually, Frost Belt was created as an opposite of Sun Belt, Bible Belt and Wheat Belt were based off the other pre-existing terms, and that part of America that has a lot of Mormons was nicknamed the Jell-O Belt because the foodstuff is apparently popular in the area.
Hello! I'm Adam Aleksic, a sophomore studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy politics, vexillology, geography, board games, conlanging, and law.