Uniform Resource Locator

URL Method of naming documents or places on the Internet, used most frequently on the World Wide Web (WWW). A URL is a string of characters that identifies the type of document, the computer the document is on, the directories and subdirectories the document is in, and the name of the document.
The part of the URL before the colon represents the scheme, or format used to retrieve the document; http means the document is on the WWW. If, instead of http, that part of the URL was ftp, it would mean that that document could be accessed through File Transfer Protocol (FTP), a format that allows a user to list files on, retrieve files from, and add files to another computer on the Internet. Some other schemes are gopher, which indicates the document is on a Gopher system, a menu-driven document delivery system for retrieving information from the Internet; news, which means the document occurs on a Usenet newsgroup, a forum in which users can post and respond to messages; and telnet, which indicates Telnet, an access method in which the user logs on to a remote computer.
The next part of the URL, www2.whitehouse.gov, is called the hostname and represents the computer on which the document can be found: www2 is the name of a specific computer at the whitehouse.gov host computer. The .gov extension identifies the computer as belonging to the United States government. Some other common extensions are .com (commercial) and .edu (education —usually a college or university).
After the computer and host names come the path, or chain of directories, on which the document is found; in this case, the only directory is WH. The last item to be listed is the document name— in this case, Welcome.html.
URLs are case-sensitive, which means that uppercase and lowercase letters are considered different letters, so a user has to enter a URL with all letters in the correct case. URLs on the WWW are accessed with browsers, or computer programs that can connect to the Internet and display Web pages.