URLs
A Uniform (or Universal) Resource Locator is a unique global Internet identifier.
They allow any object anywhere on the internet to be described, even though these objects are accessed using a variety of protocols.
URLs are composed of several parts, including the internet access protocol, the location, and the file.
URLs have been used since 1991 as the standard way to cite internet resources. They are particularly valuable in that they can be read by both machines and humans.