The word 帽子 is formed by combining the meaningful character 帽, which historically derives from a pictographic element representing a piece of cloth or covering for the head, with the character 子, which here functions not as a word for "child" but as a common, neutral suffix added to nouns. This suffix 子 often attaches to a core concept to form a concrete, everyday object, softening the pronunciation and solidifying it as a standalone, familiar item, in this case, transforming the idea of a "head covering" into the common noun for "hat" or "cap".