When combined, `星期 (xīngqī)` means “week,” literally a “star cycle,” referencing the ancient seven-day cycle based on the sun, moon, and five visible planets. Adding the number `一 (yī)` specifies it as the first day of that cycle: Monday.
The modern Chinese system for naming the days of the week is a fascinating example of linguistic logic and efficiency, contrasting sharply with the Western system. While Western languages name days after Norse and Roman gods and celestial bodies (Monday = Moon's Day, Saturday = Saturn's Day), the modern Chinese system is purely numerical. This system (`星期一`, `星期二`, `星期三`…) was adopted in the early 20th century and is now standard throughout Mainland China, Singapore, and Malaysia. It reflects a practical approach to language. Culturally, the feeling of Monday in China is very similar to that in the West. It marks the start of the work and school week and is often associated with the “Monday Blues,” a concept so universal it has its own term in Chinese: `星期一综合症 (xīngqīyī zōnghézhèng)`, or “Monday Syndrome.” On social media platforms like Weibo, you'll often see young people and office workers lamenting the end of the weekend and the start of a busy 星期一.
“星期一” is a fundamental word used constantly in daily life for scheduling, planning, and recounting events.