- Proto-Sino-Tibetan: *myəy ~ sməy/smyəy (Coblin, 1986)
- Proto-Tibeto-Burman: *mey (Matisoff, STEDT; Weidert, 1987; LaPolla, 1987; Benedict, 1972)
Comparing Chinese 火 with Proto-Tibeto-Burman *mey is problematic. Sagart (1999) reconstructed the Chinese word as /*m̥ˁɨjʔ/, citing its variant 𤈦 (an ancient Wu dialect word) as the basis for reconstructing a voiceless bilabial initial. This was however revised to a uvular initial in the Baxter-Sagart (2011) system, perhaps in accordance with Zhengzhang (2003). Li (1980) reconstructed it as *hwərX, and commented that it likely came from an earlier *hmərX. The word "fire" is classified by some to belong to the same family as some words meaning "to destroy", represented by 毁. Compare Written Tibetan སྨྱེ་བ (smye ba, “(archaic) damaged, impaired, poor quality”).
- Old Chinese:
- 火 /*qʷʰˁəjʔ/ (B-S); /*qʰʷaːlʔ/ (ZS) ("fire") (see note)
- and perhaps dialectally
- (火 in the oracle bone script)
- /*hmeᴮ/ invalid IPA characters (ᴮ) (Luangthongkum, 2013)