A URL is the address of a particular site, page, or file on the Web.

A few examples:

• A Site URL: http://www.xanga.com
• A Page URL: http://help.xanga.com/gettingstarted.htm
• A File URL: http://www.xanga.com/images/xangalogo.gif

A few rules of thumb:

• You'll usually need a site or page URL if you want to link to a page
• You'll want a file URL if you want to remotely link to a background image or music file

Hope that helps!

ps A bit of trivia: URL stands for "Universal Resource Locator".