The word "星期四" is formed by combining the term "星期", which denotes a week (derived from 星, meaning celestial body, and 期, meaning period, reflecting the historical association of days with astrological bodies), with the number "四" meaning four, indicating its position as the fourth day in the conventional seven-day week sequence. This systematic approach creates a literal meaning of "week four" for Thursday, aligning with modern Chinese weekday naming where days are numbered sequentially from Monday onward.