Where does “炭水化物” come from?

炭水化物 (Japanese) comes from Japanese 炭, from Middle Chinese 炭.

炭水化物 (Japanese): carbohydrates

Definitions

Step	Language	Word	Meaning
1	Japanese	炭	charcoal; coal
2	Middle Chinese	炭	—

炭水化物 — Etymology, Origin & Word History | Etymology Explorer