星期 (xīngqī): week

Meanings

Originally based on the seven-day cycle of the celestial bodies (sun, moon, and five visible planets).

一个星期有七天。

Yí gè xīngqī yǒu qī tiān.

A week has seven days.

今天星期几？

Jīntiān xīngqī jǐ?

What day of the week is today?

grammar

Days of the week: 星期一 (Mon) through 星期六 (Sat) use numbers 1-6. Sunday is 星期天 or 星期日 (not 星期七).

usage

周 is a shorter alternative: 周一 (Monday), 周末 (weekend). It's more common in formal or written contexts.

星 xīng

期 qī