Where does “くに” come from?

くに (Old Japanese) comes from Japanese 訓, from Middle Chinese 訓.

Ancestry of “くに”, step by step

StepLanguageWordMeaning
1Japanese訓kun'yomi
2Middle Chinese訓—
Every word from Middle Chinese 訓 →Every word from Japanese 訓 →
くに — Etymology, Origin & Word History | Etymology Explorer