A PNR number is a cataloguing record in travel terminology, explains the Practical Nomad. PNR stands for "passenger name record," and it's a measurement value placed inside the database of a computer reservation system, or CRS.
A PNR contains a variety of information about a person or group of people traveling together from one place to another. A PNR number keeps record of several sets of data. The most important thing held in a PNR number is the itinerary of its assigned traveller, according to the Practical Nomad. Airlines first used PNR numbers to allow the quick exchange of a passenger's information between different airline agencies.