The hosted domains feature of a web hosting account refers to the amount of registered domains that one could add in the very same account. Registering a domain address and hosting it are 2 different services although a lot of people consider them to be the exact same thing. While the registration ensures that you become the owner of a given domain, the hosting part is what actually enables you to have a site since this is where your files and email messages are going to be. As these are 2 different services, it is possible to register a new domain with one company and host it with another by changing its name servers (DNS) - the domain address shall work in the exact same way as if it was registered and hosted with the same company. Also, it is very important to know that changing the hosting means pointing the domain address to another company and not transferring it.