The word 肾脏 (shènzàng), meaning "kidney", is a compound noun formed through semantic complementation, where both characters contribute related meanings. The first character, 肾 (shèn), specifically means "kidney" on its own, while the second, 脏 (zàng), is a broad term for "internal organ" (often used in medical contexts like 心脏, heart, or 肝脏, liver). By combining them, the word creates a more precise and formal biological term: 肾 specifies the organ type, and 脏 classifies it within the visceral system, resulting in a complete, technical designation equivalent to the English "kidney organ". This construction is typical in Chinese for forming precise anatomical terminology.