How come that the character 星 (star) is used in the word for week 星期?

期 means a period of time, but why is week "star"?


1 Answer 1


In ancient China, makers of calendars tried to relate rotation of stars or star constellations with mythological deities. In fact, Chinese calendar doesn't carry the concept of week.

European names for "week days" are represented by Greek/Roman mythological deities. European creating the "week" concept from there.

Chinese scholar use 星期 to represent week when China adapt the universal international calendar, which means the day/period of the constellation/star deity complete their "duty roster". Only Sunday 星期日/天 follow the Roman/Greek, which may be due to influence of European missionary.


In 1905, Qing Dynasty education officer Yuan-Jia-Gu establish translation and library division for the education department to standardised technical jargon. This is when Chinese use 星期 to represent the week.

On the other hand, Japanese is using the Roman/Greek deity to represent days, as in Europe. Japan is using 曜 that carry similar meaning as constellation/star.

Note : Johann Adam Schall von Bell(May 1, 1592 – August 15, 1666) is helping Qing dynasty perfecting the Chinese calendar. Chinese has stronger cultural interaction with Europe than many can imagine.

(update) for those curious about Japan week days

  • 星期一:月曜日 Monday, Máni, avatar of moon
  • 星期二:火曜日 Tuesday , The god Tiw, identified with Mars
  • 星期三:水曜日 Wednesday, Germanic god Woden, avatar of Mercury
  • 星期四:木曜日 Thursday, Thor's (Jupiter's) day
  • 星期五:金曜日 Friday, goddess Frigg, Roman goddess Venus
  • 星期六:土曜日 Saturday, Roman god Saturn
  • 星期日:日曜日 Sunday, Sól, avatar of Sun
  • 1
    The 七曜 system is attested back from the 4th century AD in China. Also, in addition to Japanese, the Korean language also preserves the 七曜 system.
    – Michaelyus
    Commented Feb 21, 2017 at 17:00
  • @Michaelyus Korea once upon a time colonised by Japan.
    – mootmoot
    Commented Feb 22, 2017 at 16:12

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