A taxi medallion, also known as a CPNC, is a transferable permit in the United States allowing a taxicab to operate. Several major cities in the US use these in their taxi licensing systems, including New York City, Boston, Chicago, Philadelphia, and San Francisco.

A taxi, also known as a taxicab or simply a cab, is a type of vehicle for hire with a driver, used by a single passenger or small group of passengers, often for a non-shared ride. A taxicab conveys passengers between locations of their choice. This differs from public transport where the pick-up and drop-off locations are decided by the service provider, not by the customers, although demand responsive transport and share taxis provide a hybrid bus/taxi mode.