Definition: URL

(Uniform Resource Locator) The address that defines the route to a file on an Internet server (Web server, mail server, etc.). URLs are typed into a Web browser to access Web pages and files, and URLs are embedded within the pages themselves as links (see hypertext).

The URL contains the protocol prefix, port number, domain name, subdirectory names and file name. If a port number is not stated in the address, port 80 is used as the default for Web traffic (HTTP traffic). See port 80 and TCP/IP port.

Downloading the Home Page
To access a home page on a website, only the protocol and domain name are required. For example, http://www.computerlanguage.com retrieves the home page of the Computer Language Company's website. HTTP is the Web protocol, and WWW.COMPUTERLANGUAGE.COM is the domain name. Browsers default to the http:// prefix so only the www.computerlanguage.com needs to be typed in. In fact, you can usually omit the WWW and dot, because most websites treat blank hostnames as "www" hostnames. Sometimes, you can even omit the .com, and the browser fills it in automatically.

Another Web Page
If a page is not the home page, its name has to be part of the address, and a slash is used to separate it from the domain name. For example http://www.computerlanguage.com/about.htm points to the About page (about.htm file). See URL shortening.

The Full Path
If a page is stored in a subdirectory (folder within a folder), its name is also separated by a slash, and subdirectories can be several levels deep. Follow the example below:

 Hypothetical URL:

 http://www.car.com/kia/used/2008.html

 This:          Is the:

 http://        protocol

 www.car.com/   domain

 kia/           subdirectory

 used/          subdirectory

 2008.html      file (Web page)

Is It a URL or a URI?
Technically, a URL is a type of uniform resource identifier (URI). Since most URIs are URLs, "URL" is the term more commonly heard. See URI.