Definition of "PNR"

(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.  examples

(aviation, navigation) Initialism of point of no return.  examples

(Philippines) Initialism of Philippine National Railways (“the main rail operator in the Philippines, particularly around Luzon”).  examples