The hosted domains feature of a hosting account denotes the amount of registered domain names that one can include within the very same account. Registering a domain address and hosting it are 2 completely different services even though many people consider them to be the very same thing. While the registration ensures that you become the owner of a given domain address, the hosting aspect is what actually enables you to have a site since this is where your data and emails are going to be. Since these are 2 independent 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 shall work in the exact same way just as if it was registered and hosted using the same company. It's also very important to know that changing the hosting means pointing the domain to an alternative company and not transferring it.