The word **大巴** (dàbā) is a compound noun formed through a process of semantic combination and lexical shortening. The first character, **大** (dà), means "big" or "large," directly describing the object's size. The second character, **巴** (bā), is a truncated form of the loanword **巴士** (bāshì), which itself is a phonetic borrowing from the English word "bus." Therefore, **大巴** literally and functionally means "big bus," specifically referring to a coach or full-sized motorcoach, as distinct from a smaller public transit bus (巴士 or 公共汽车).