The Chinese word **城墙 (chéngqiáng)**, meaning "city wall," is a **compound noun** formed by combining two meaningful characters: **城 (chéng)**, which means "city" or "walled city," and **墙 (qiáng)**, which means "wall." Its formation follows a common **modifier-head** structure in Chinese, where the first character **城** specifies the type or purpose of the second character **墙**, creating a precise term for the specific defensive walls that historically surrounded and defined Chinese cities.