The hosted domains feature of a website hosting account denotes the amount of registered domain names which you can add within the very same account. Registering a domain and hosting it are 2 different services even though many people consider them to be the same thing. While the registration ensures that you become the owner of a given domain, the hosting element is what really enables you to have a site as 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 name with one company and host it with another one by modifying its name servers (DNS) - the domain address is going to work in the exact same way just as if it was registered and hosted using the same company. It is also extremely important to know that changing the hosting means pointing the domain to a different company and not transferring it.