The word casserole was borrowed in the early 1700s from French, where it meant "sauce pan." The -erole part is a lengthened version of the diminutive suffix -ole that was tacked on in the sixteenth century to casse, which just meant "pan," and that traces to the Medieval Latin word cattia, meaning either "pan" or "vessel." Because language is messy, there was probably also some influence from the Provençal noun cassa, which also meant "pan" and probably comes from Latin capsa, meaning "box." However, it's thought that cattia comes from a diminutive of the Greek word kyathos, which was used to describe a special kind of wine vase, similar to a ladle, with a long and looping handle. That's where the trail runs cold, although some think that it could be related to the Proto-Indo-European reconstruction kewh, meaning "to swell." In the late 1880s, casserole started to be extended to the dishes cooked in it, through phrases like en casserole or à la casserole.
Hello! I'm Adam Aleksic, a senior studying government and linguistics at Harvard University, where I co-founded the Harvard Undergraduate Linguistics Society. In addition to etymology, I also really enjoy trivia, politics, vexillology, geography, board games, conlanging, art history, and law.