Computers communicate by using numbers, called IP addresses, to contact each other, much like you use a phone number to dial a specific person’s phone. Domain names on the internet are much like entries in a phone book. The phone book tells people looking for a business what the entries are just as a domain tells people (i.e. their computers) that a domain is hosted on the server.
The web-hosting or server is the place, typically on a server, where you store all the text, script, images, videos and other information that help create your website. Domains are the Internet signposts that show web browsers where to find that information. The two can be totally independent or completely intertwined.