When combined, 礼拜 (lǐbài) means “(to) worship” or “a religious service.” Adding 日 (rì), meaning “day,” creates 礼拜日 (lǐbàirì)—the “day of worship,” or Sunday.
The term 礼拜日 is a direct linguistic footprint of Western cultural influence, specifically Christian missionaries, in China. Before the widespread use of the modern `星期 (xīngqī)` system, there were various ways of marking time. Missionaries introduced the concept of a seven-day week with a dedicated day for worship, which they called `礼拜` (lǐbài). Thus, Sunday became known as `礼拜日`. In contrast to the Western concept of “Sunday,” which has pre-Christian pagan roots (Sun's Day), `礼拜日` is explicitly tied to the *act* of worship. This makes its origin story more transparent within the word itself. While its religious connection is the source, the term has become secularized over time. However, it still stands in contrast to its synonyms:
Using `礼拜日` today does not imply the speaker is religious, but it carries a slightly more classic, sometimes even literary, flavor compared to the others.
In daily conversation, especially in northern China, 星期天 (xīngqītiān) is the most frequently heard term for Sunday. 星期日 (xīngqīrì) and 周日 (zhōurì) are more common in written Chinese, news reports, and official schedules. 礼拜日 (lǐbàirì) fits comfortably in both spoken and written contexts. It's universally understood and doesn't sound out of place, but it's used less frequently than the `星期` or `周` variations. You might hear it used by older generations, in certain regions, or in contexts where a slightly more formal or traditional tone is desired. Its connotation is entirely neutral.