The definition of URL

A Uniform Resource Locator is basically just an address for a file that can be given to a browser. It starts with a protocol type (such as http, ftp, or gopher) and is followed by a colon, machine name, and file name in UNIX style. Optionally an octothorpe character "#" and and arguments will follow the file name; this can be used to further define position within a page and perform a few other tricks. Similar to but less general than a URI.