The hosted domains feature of a hosting account denotes the number of registered domain names that you could add in the exact same account. Registering a domain and hosting it are two totally 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 name, the hosting part is what actually permits you to have a website because this is where your data and e-mails are going to be. Since these are 2 independent services, you'll be able to register a new domain with one company and host it with another by changing its name servers (DNS) - the domain is going to work in the exact same way just as if it was registered and hosted with the same company. Also, it is very important to know that changing the hosting means directing the domain to a different company and not transferring it.