A URN (Uniform Resource Name) is a specific type of URI (Uniform Resource Identifier) that is used to uniquely identify resources by their names in a persistent and location-independent manner.
Unlike URLs, which identify resources by their locations, URNs identify resources by their names, making them suitable for resources that may change location over time or do not have a specific location. URNs are intended to be unique and persistent, ensuring that the same URN will always refer to the same resource, even if its location changes.
Example: Here is an example of a URN:
urn:isbn:0451450523
This URN identifies a book by its ISBN (International Standard Book Number), regardless of where the book is located. The URN does not specify the location of the book but uniquely identifies it by its name.