An absolute path requires all parts leading to a server's physical file or directory location. Example: /home/apple/htdocs/images/pix1.jpg. This is used primarily in server scripts and never for the public page view.
A relative path is devoid of a protocol and top level domain. It is related to the URL where a file or directory is located. Example: Instead of /home/apple/htdocs/images/shwoimage/pix1.jpg which is the full URL, the relative URL would be /images/showimage/pix1.jpg. It can only be used on the same hosting server where the image is stored, meaning it cannot be relative to a file on another server.
An acronym for Uniform Resource Locator. This is the protocol plus the domain name and extension. Example http://www.websitedons.com
Web hosting is a service provided by multiple vendors around the world at a nominal recurring fee or free. In many cases the service will have limitations on storage, bandwidth, email accounts and a number of other items, but the current trend is unlimited hosting and no limits on all other factors.
Websites need a point of distribution and a web hosting server is that point. It is a computer located generally at a data-center which has the massive high speed connections capable of delivering website files to thousands of visitors at the same moment.
An acronym for What You See Is What You Get. This just means that the way your content is displayed as you are editing with an editor, such is the way it will be displayed when published to the website. Types of website WYSIWYG editors are Adobe Dreamweaver, FCK Editor, TinyMCE