The word "星期二" (Tuesday) is formed by combining the term "星期", meaning "week", which itself derives from the concept of a "star period" historically linked to astronomical cycles, with the numeral "二" meaning "two", indicating the second day in the seven-day weekly sequence adopted from Western calendrical systems. This structure follows a consistent pattern where days from Monday to Saturday are designated by adding numerals one through six to "星期", creating a logical and sequential naming convention for the days of the week.