The word calzone was first used in the United States in 1933, but it was coined in Italian all the way back in the eighteenth century when the food was invented. The term had a literal definition of "trouser leg", apparently because of visual similarity. That's from the earlier word calza, meaning "sock", which comes from Latin calceus, meaning "shoe". The root there is calx, the word for "heel", and the suffix -eus, which is just the masculine nominative suffix. Calx, which is unrelated to the word for "limestone", has an uncertain origin, but it might be from Proto-Indo-European kel ("to bend"), from PIE khlk ("hip"), or even Etruscan. Usage of the word calzone peaked in the mid-1990s.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.