I have read https://www.jstor.org/stable/10.1525/gfc.2002.2.1.80 and it says: “Contrary to popular etymology, the word phO has nothing to do with the French pot au feu, the one-pot beef and vegetable dish. Nguyen Ngoc Bich believes that phO derives from the Mandarin Chinese character fen, meaning “rice noodles.” As Chinese street vendors hawked their soup around town, he says, they would call out “fe……n,” the first part of which sounded something like phO to the Vietnamese ear.2 “When the refugees imported this soup to Vietnam, a vendor would not call out ‘fe…n,’ which in Vietnamese means ‘excrement.’3 The Vietnamese simply dropped the final “n” and created a new word meaning “beef noodle soup.””
The etymolnline entry says " probably from French feu “fire” “as in pot-au-feu, a stew of meat and vegetables of which the broth is drunk separately as a soup”"
I’ll think about this one. I allow this guy being quoted probably knows more Vietnamese and Chinese than I do, but, I’m also hesitant to use information from one random guy who got quoted in a magazine article contradicting the OED just because he did. We get bad “it seems to me…” kind of etymologies submitted all the time, and they’re found in print often enough as well. Got to weigh them as to how likely they are to really be better information than what is out there already.
Right now I’d like to see more about the guy’s method for concluding this. For instance, are these all period-correct words for when Pho first appeared in the source language?
My research is indicating that older versions of pho didn’t necessarily include noodles, so, his claim it’s from the word for rice noodles seems improbable.
Alright. I was able to find the “fen” theory quoted in Encyclopedia Britannica, which is a more reputable publication from which I can quote. It doesn’t dismiss the feu theory, however, it just calls it “equally likely.” I added both to the entry.