From Proto-Tai *wɤjᴬ (“fire”). Cognate with Thai ไฟ (fai), Northern Thai ᨼᩱ (fai), Lao ໄຟ (fai), Lü ᦺᦝ (fay), Tai Dam ꪼꪡ, Shan ၽႆး (pháy) or ၾႆး (fáy), Tai Nüa ᥜᥭᥰ (fay2), Zhuang feiz, Bouyei fix.
วี๊ (transliteration needed)