A host is a server which provides a home for your website on the World Wide Web. Just as your computer contains all your files, so a host contains all the files needed to run your website. Why can’t you just keep all those files on your own computer? Because that would mean users would have to connect directly to your computer to see your website. Not a good idea—it wouldn’t be secure and it would make your machine run like a tired snail. With a host, you can simply upload everything you need to the server and your users can then connect there to see your site. It lets the site run faster and allows it to have all the security and extras it needs.
The rest of the article can be found at The Great Ideazine