The idiom **齐心协力** (qí xīn xié lì) is a classical four-character expression formed through parallel structure and semantic reinforcement. It combines two complementary pairs: **齐心** (to be of one heart/mind) and **协力** (to unite strength/effort). The first character **齐** means "united" or "together," modifying **心** (heart/mind), while **协** means "in harmony" or "jointly," modifying **力** (strength/power). The compound thus merges the concepts of mental unity and physical cooperation, creating a holistic meaning of "to work together as one with concerted will and shared effort." This structure exemplifies a common pattern in Chinese idioms where synonymous or closely related terms are paired to intensify and complete the overall meaning.