The hosted domains feature of a web hosting account denotes the amount of registered domains which you could include within the very same account. Registering a domain address and hosting it are 2 completely different services although a lot of people consider them to be the same thing. While the registration means that you become the owner of a specific domain name, the hosting element is what actually enables you to have a site as this is where your data and emails are going to be. As these are 2 separate services, you are able to register a new domain with one company and host it with another by modifying its name servers (DNS) - the domain name will work in the exact same way as if it was registered and hosted with the exact same company. It is also important to know that changing the hosting means directing the domain to another company and not transferring it.