noun: (travel, aviation) Initialism of passenger name record: the complete details of a passenger's booking, including itinerary, contact details, and special requests; or the unique alphanumeric identifier for each booking.
noun: (aviation, navigation) Initialism of point of no return. [(aviation) The point in an aircraft's flight when there is insufficient fuel to reverse direction and return to the place of origin.]
noun: (Philippines) Initialism of Philippine National Railways (“the main rail operator in the Philippines, particularly around Luzon”).