One could say that a domain is an internet address and must be unique.
For instance the name of this website www.ctrbusiness.com is unique on the internet and is for my exclusive use.
Not all registered names result in websites, there are many people who reserve a name and then "park" it, just so nobody else will obtain the exclusive rights to the use of that name.
The organization that controls the internet domains is Icann.org
As you probably know internet addresses are usually in the form of somename.extension.
Extensions are like neighbourhoods of the internet.
Below are some of the more popular ones:
.com for "commercial,". This is probably the most used and known extension in the world. .net for "network," This is mostly used by Internet service providers. .org for "organization," and is primarily used by non-profits groups or trade associations. .biz for "Business" is used for small business Web sites. .info for "Information" and resource Web sites. .us for American Web sites. lots of countries have their own extensions. .tv for "Television" and is for entertainment media related Web sites. .name for personal use names. for example johndoe.name would indicate John Doe's personal website
There are also many country specific extensions, like,
.be -> Belgium,
.nl -> Netherlands
.us -> USA etc.
Once a domain name has been registered, its dsn server addressed need to be maintained, so the computers on the internet know where to send traffic for this doman.
Also domain registration expire after a certain time, and if you do not renew then someone else can register it.
When you Host your website with us, we will take care of all these things, you just pick a domain name you like and that is available, and we will set up everything needed to make it happen.