Absolute links are links that are links that are in their entirety that point to a specific website. They contain the normal http://, the www., and the entire URL and the .com, .net. or .org domains. Here is an example:
<a href="http://www.visionary.com/index.html">Visionary Homepage</a>
A relative link is completely different. A relative link refers to another page within a website. For example if you are on the Visionary website and someone clicks on the contact page, you are clicking on a link that is relative, or in relation to the visionary website. Here is an example:
<a href="../contact.html">Contact Us</a>
/ tells the browser to go out of the current directory and go to the contact.html file. Keep in mind that this will only work inside of website. You can't use a relative link to connect to a page in another website, because the browser won't know what it is looking for.