Chinese dish of stir-fried noodles served with sauce, 1898, American English, from Chinese ch'ao mien, said to mean "fried dough."
Whereas the majority of Chinese culinary terms in English have become established since the Second World War, with the rise of the Chinese restaurant, chow mein belongs to an earlier stratum, introduced via the West Coast of America in the early years of the twentieth century, and institutionalized in the 1920s and 1930s as the archetypal Sino-American dish. [Ayto, "Diner's Dictionary"]
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Harper, D. (n.d.). Etymology of mein. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/mein