The term "块头" is a Chinese compound word formed through semantic combination, where "块" (kuài) originally means a lump, chunk, or mass of something solid, connoting bulk and substantial form, while "头" (tóu) means head, but in this context functions as a nominal suffix that often generalizes or refers to a related aspect of a concept. Together, they create a metaphorical meaning, likening a person's physical build or stature to a solid, bulky mass, thus coming to refer specifically to the size of a person's body or physique.