The word sushi was borrowed in 1893 as American society slowly began a long history of adopting pieces of Japanese culture (after which it steadily grew in usage to a peak today). There's a misconception that the name has something to do with fish, but in the original Japanese, sushi actually meant "sour rice", in reference to the outside of the delicacy. Earlier, with a different character but the same pronunciation, that meant "sour" or "tasting of vinegar", and further back there was a word sounding like su, which just meant "vinegar". -Shi is an adjectival suffix tracing to the Heian period. The etymology of su is uncertain. There's a theory that takes it to Proto-Japonic and another going back to Chinese, so we're not even sure about the language family there. Still very interesting though!
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.