Where does “いそち” come from?

いそち (Japanese) comes from Japanese 五十, from Middle Chinese こしゆう.

Ancestry of “いそち”, step by step

いそち traces back through two separate lines of ancestry.

via Japanese 五十

StepLanguageWordMeaning
1Japanese五十fifty, 50; a fifty-year-old; a large quantity
2Middle Chineseこしゆう—

via Old Japanese つ

StepLanguageWordMeaning
1Old Japaneseつ—

Words derived from “いそち”

Every word from Middle Chinese こしゆう →Every word from Japanese 五十 →