| standardized character string used for locating and accessing an Internet resource
NOTE 1 The general form of an URL (see RFC 1738) is as follows:
In some cases, certain parts may be omitted.
<scheme> is the access protocol, e.g. http, ftp, or news.
<user>, <password> and <port> are optional, and the separators “:” (colon) and “@” are omitted when unnecessary.
<host> is an IP address or a fully qualified host name, and is omitted for local Internet resources.
<port> is an address for protocols on the TCP layer and has a default which depends on the protocol.
<url-path> indicates the access to a resource inside the host. If it is omitted, a default resource is accessed.
Examples of URLs identifying a Web site, a file, or a service:
“http://www.iec.ch” is the URL of the site of the International Electrotechnical Commission. In this URL, “ch” is the top-level domain name. It should be noted that besides <scheme> this URL contains only the part <host>.
“http://www.iec.ch/about/mission-e.htm” is the URL of a page giving in English the IEC mission and objectives. This file is accessible by the HTTP protocol.
“news:comp.os.unix” is the URL of a forum whose name is “comp.os.unix” and “news:XYZ123@news.iso.org” might be the URL of an article, the identifier of which is “XYZ123”, stored on the host “news.iso.org”.
NOTE 2 URL is an acronym of the full term "uniform resource locator".