The hosted domains feature of a hosting account refers to the number of registered domains which you can include within the same account. Registering a domain and hosting it are two completely different services although some people consider them to be the same thing. While the registration means you become the owner of a given domain name, the hosting element is what really enables you to have a website since this is where your files and emails will be. Because these are two separate services, you are able to register a new domain with one company and host it with another by changing its name servers (DNS) - the domain name is going to work in the exact same way as if it was registered and hosted using the same company. Also, it is extremely important to know that changing the hosting means pointing the domain to a different company and not transferring it.