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