The hosted domains feature of a web hosting account refers to the amount of registered domain names that you can add within the same account. Registering a domain address and hosting it are two totally different services although a lot of people consider them to be the very same thing. While the registration means that you become the owner of a certain domain name, the hosting part is what in fact permits you to have a site as this is where your data and emails are going to be. Because these are 2 different services, you are able to register a new domain with one company and host it with another one by modifying its name servers (DNS) - the domain will work in the exact same way just as if it was registered and hosted with the same company. Additionally, it is important to know that changing the hosting means pointing the domain to a different company and not transferring it.