Where does “天皇誕生日” come from?

天皇誕生日 (Chinese) comes from Japanese 天皇誕生日, from Japanese 誕生日, from Japanese 日, from Old Japanese 日, from Proto-Japonic *pi — day, sun.

天皇誕生日 (Chinese): The Emperor's Birthday, the birthday of a Japanese emperor

Definitions

  1. The Emperor's Birthday, the birthday of a Japanese emperor

Ancestry of “天皇誕生日”, step by step

StepLanguageWordMeaning
1Japanese天皇誕生日a national holiday in Japan on the birthday of the 今上天皇, currently February 23
2Japanese誕生日a birthday
3Japanese日Sunday
4Old Japanese日the sun; sunlight, sunshine; daytime, daylight
5Proto-Japonic*piday, sun
Every word from Proto-Japonic *pi →Every word from Old Japanese 日 →Every word from Japanese 日 →