The word "肚子" is formed by combining the character "肚", meaning "belly", with the suffix "子", which nominalizes it to create a concrete noun for the abdomen. The character "肚" itself consists of the radical "月" (a variant of "肉", indicating flesh or body parts) and the component "土" (primarily providing phonetic guidance), while "子" in this context serves as a grammatical appendage without independent meaning, resulting in the standard term for stomach or belly.