牌照 literally means 'sign + illumination'—a historical reference to official plaques or tokens issued by authorities to authorize use or operation. In modern usage, it most commonly refers to a vehicle license plate: the metal or plastic plate affixed to cars, motorcycles, or trucks displaying a unique alphanumeric code assigned by traffic authorities. It serves as legal proof that the vehicle is registered and permitted for road use.

Less commonly, 牌照 can also mean an official permit or license in broader administrative contexts—for example, a business operating license or a special-use permit—but this usage is formal and increasingly rare outside legal or bureaucratic documents. The term emphasizes official authorization rather than personal qualification, distinguishing it from words like 证书 (certificate) or 资格 (qualification). It’s almost always used as a noun and rarely appears in verb phrases.