Where does “木曜日” come from?

木曜日 (Japanese) comes from Japanese 日, from Old Japanese 日, from Proto-Japonic *pi — day, sun.

木曜日 (Japanese): Thursday

Definitions

  1. Thursday

Ancestry of “木曜日”, step by step

木曜日 traces back through two separate lines of ancestry.

via Japanese 日

StepLanguageWordMeaning
1Japanese日Sunday
2Old Japanese日the sun; sunlight, sunshine; daytime, daylight
3Proto-Japonic*piday, sun

via Japanese 木曜

StepLanguageWordMeaning
1Japanese木曜planet Jupiter; Thursday
Every word from Proto-Japonic *pi →Every word from Old Japanese 日 →Every word from Japanese 日 →