The word 盔甲 is a classic example of a Chinese compound word formed by combining two semantically related characters, each representing a key component of the whole. 盔 (kuī) specifically refers to the protective helmet worn on the head, while 甲 (jiǎ) originally denoted the hard, shell-like body armor (often made of leather or metal plates) protecting the torso. Together, through the common Chinese word-formation process of coordinative compounding, they merge to form the single, more general term for a full suit of armor, encompassing both the helmet and the body protection.