What is a Domain?
In order to have a website online you need:
- A domain; www.thisisadomain.com
- Hosting; A place where the database and files are stored.
The Hosting is connected to your domain via nameservers. Nameservers are ways to identify a server i.e. the location where your site is "saved". Your domain can be registered with a different provider than your hosting.
Example by Analogy:
Domain > Hosting/Server IP > Website
i.e. We have a domain > The Files and Databases are at this IP Address > Show the Site
Street Name > House/Address > You
i.e. Your Street Name > All your things are in this home at this Address > Show The House
Related: Transferring Ownership of a Domain.