The Chinese word 牙膏 (yágāo), meaning "toothpaste", is a straightforward compound noun formed by combining two meaningful characters: 牙 (yá), which means "tooth", and 膏 (gāo), which means "paste", "ointment", or "cream". It follows a common modifier-head structure in Chinese, where the first character 牙 specifies the type or purpose (for teeth), and the second character 膏 indicates the general category of substance (a paste-like material). This logical combination directly describes the product's function and form, creating a transparent and easily understandable word.