What is an URL (Uniform Resource Locator)

This is the standard way to give the address of any resource on the internet whether or not is part of the World Wide Web (www), but as long as it can be accessed with an hyper-text transfer protocol or file transfer protocol address call, and is a part of a server listed on the canonical domain name registration tables to resolve to an IP address.
 
The term "resource" here is used to refer to any web page, graphic, sound file, or any other resource which one can call from a URL.  A URL will begin with http:// (hypertext transfer protocol) or https:// (hypertext transfer protocol secure) or ftp:// (file transfer protocol) with few or no other variants.   Note that a URL can refer directly to an Internet Protocol address (IP address) such as this:  http://192.168.1.1.