Where does “平日” come from?

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

平日 (Japanese): a weekday, an ordinary day

Definitions

  1. a weekday, an ordinary day

Ancestry of “平日”, step by step

平日 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 平

StepLanguageWordMeaning
1Japanese平something flat; flattened; something ordinary,...
2Middle Chinese平—
Every word from Proto-Japonic *pi →Every word from Old Japanese 日 →Every word from Japanese 日 →