'Vietnamese noodles, served in beef (or chicken) broth'
Pronounced fuh. You can often see it in Asian menus, also in the US.
Etymology: either from French feu 'fire' (the French had a large colonial influence in Vietnam at the end of the 19th century, beginning of the 20th), or from Chinese 粉 ('noodles').
The spelling in Vietnamese is phở, where the diacritic on the vowel indicate a tone: this is the hỏitone: mid-dipping-rising (https://en.wikipedia.org/wiki/Vietnamese_language#Vowels). The second diacritic indicates the vowel is long (or: not short).