Absolute URL

The word absolute, in English, means "not dependent on anything else". It also means "free from doubt".
An Absolute URL is, thus, something that is independent or free from any relationship. When you use an absolute URL, you point directly to a file. Hence, an absolute URL specifies the exact location of a file/directory on the internet. It also follows that each absolute URL is unique, which means that if two URLs are identical, they point to the same file.

For example:
https://www.webdevelopersnotes.com/images/email.gif specifies an image file email.gif located in the images directory, under www.webdevelopersnotes.com domain name.

Similarly, the absolute URL of the document you are viewing is https://www.webdevelopersnotes.com/design/ relative_and_absolute_urls.php3 which is a page in the directory called design on this web site.

Absolute paths or URLs

Absolute paths are called that because they refer to the very specific location, including the domain name. The absolute path to a Web element is also often referred to as the URL. For example, the absolute path to this Web page is: https://webdesign.about.com/library/weekly/aa040502a.htm

You typically use the absolute path with the domain to point to Web elements that are on another domain than your own. For example, if I want to link to the Graphic Design Guide's site - I need to include the domain in the URL: https://graphicdesign.about.com/. So a link to her glossary entry would look like this:
...

If you're referring to a Web element that is on the same domain that you're on, you don't need to use the domain name in the path of your link. Simply leave off the domain, but be sure to include the first slash (/) after the domain name.

For example, the Beginner's Resource Center has the URL: https://webdesign.about.com/library/beginning/bl_begin.htm If I were to link to this URL from another page on my site, I could link to it in this way:
...

It is a good idea to use absolute paths, without the domain name, on most Web sites. This format insures that the link or image will be usable no matter where you place the page. This may seem like a silly reason to use longer links, but if you share code across multiple pages and directories on your site, using absolute paths will speed up your maintenance.