Where does “螢” come from?

螢 (Japanese) comes from Japanese 蛍, from Middle Chinese 螢.

Ancestry of “螢”, step by step

StepLanguageWordMeaning
1Japanese蛍a firefly
2Middle Chinese螢—
Every word from Middle Chinese 螢 →Every word from Japanese 蛍 →
螢 — Etymology, Origin & Word History | Etymology Explorer