The plural of URL: uniform resource locator. A URL is a web address like http://www.cocoadev.com/index.pl or a ftp address like a ftp-link or a file address like file:///Developer/Documentation/faq.html. There are many other URL schemes out there. The specification defining what a URL is is at http://www.w3.org/Addressing/URL/url-spec.html
Cocoa Deals with General/URLs with the General/NSURL class, which is toll-free bridged to General/CFURL.