The difference is simple as: a domain must be registered by a domain registration company and then that domain name must be hosted on the internet through a web hosting company.
When you get a guests on your website, they use your domain name to view your website. As easy as it seems, there is a process that happens from the time that the site visitor is typing in your domain and presses enter.

When a site visitor enters your domain name into a browser, the domain is then translated into your server IP address,  then the server sends that user to your site files, which means that their browser shows them as a typical web-page.

Many years ago the websites were used only by educational institutions and government agencies in order to make information available to each other via text-only websites. Nowadays the web is widely opened to the public and there are so many types of websites that is difficult to distinguish them.
Before trying to categorize the web site, let’s see how can we define a website? A Website is a set of related web pages served from a single web domain. A website is hosted on at least one web server, accessible via a network such as the Internet. All publicly accessible websites collectively constitute the World Wide Web.