Have you ever carefully noticed the string in the address bar of your browser? What is it? Is it a URI or URL or URN? Some of us can’t differentiate between URI and URL and URN. Some non technical persons even don’t know the terms URI and URN. They just call that string a URL. Let’s understand this concept in deep.
URI - Uniform Resource Indicator
URL - Uniform Resource Locator
URN - Unifrorm Resource Name
URI: A URI indicates the name and the address of the resource on the web. The URI is further subdivided into URL and URI. It means URL and URI are the components of URI. definition
URL: A URL is the address of some resource on the web. A URL defines how the resource can be obtained and from where it can be obtained.
URN: A URN is the name of some resource on the web. A URN does not imply the availability of the identified resource and never tells about how the resource can be obtained.
So, one can say URI = URL + URN
If i say “My name is Roy”, then it will be a URN, just telling the name of a person not the proper location.
If i say “I live in New York”, then it will be a URL, telling me the location of a person.
If i say “My name is Roy and I live in New York”, then its proprer URI.
Ambiguity: Its the matter of ambiguity whether the term URL is deprecated or not. Some argue yes and some no. Some say that the more correct term is URI, used in technical documentation. All URIs are means to access a resource on the Internet and are a technical short hand used to link to the resource. URIs always designate a method to access the resource and designate the specific resource to be accessed. So should we use the term URI instead of most popular term URL?
URI is an abstract concept while URL and URN are the concrete implementations of a URI and one should always know the difference among all the three.