Where does “日進月歩” come from?

日進月歩 (Japanese) comes from Japanese 日月, from Japanese 月, from Old Japanese 月, from Proto-Japonic tukuy, from Proto-Japonic tuku.

日進月歩 (Japanese): daily and monthly progress; steady progress; rapid progress

Definitions

  1. daily and monthly progress; steady progress; rapid progress

Ancestry of “日進月歩”, step by step

日進月歩 traces back through two separate lines of ancestry.

via Japanese 日月

StepLanguageWordMeaning
1Japanese日月sun and moon; life, livelihood
2Japanesethe moon; a natural satellite; moonlight,...
3Old Japanesethe moon; a month; a menstrual cycle,...
4Proto-Japonictukuymoon
5Proto-Japonictuku

via Japanese 進歩

StepLanguageWordMeaning
1Japanese進歩progress; improvements in social welfare
Every word from Proto-Japonic tukuEvery word from Proto-Japonic tukuyEvery word from Old Japanese
日進月歩 — Etymology, Origin & Word History | Etymology Explorer