The word "大爷" is a compound noun formed by combining the character "大" (dà), meaning "big" or "elder," with "爷" (yé), a term for "grandfather" or a respectful form of address for an older male. Together, they semantically create a term denoting an "elder uncle" (specifically, one's father's elder brother) in a familial context. However, its meaning extends beyond kinship; when used as a polite form of address in society, it respectfully refers to an older gentleman, often conveying a sense of seniority and authority. The formation thus follows a common Chinese pattern of adjective + noun to specify a particular social or familial role, with the tone of pronunciation (dà yé vs. dà ye) sometimes differentiating the respectful address from the kinship term.