The word 避孕套 is formed by combining three meaningful components into a single conceptual unit: "避" (bì), meaning to avoid or prevent; "孕" (yùn), meaning pregnancy; and "套" (tào), meaning a sheath or cover. These parts are assembled in a logical, descriptive sequence to create a direct, functional name for the object: it is a "cover" whose purpose is to "avoid pregnancy". The formation is purely semantic, building a compound idea where each character contributes a essential piece of the overall meaning, pictorially defining the item by its primary use and physical form.