What is a Domain?
A domain name simply makes the IP address ( a long string of numbers like 18.104.22.168) into a name like Websitewag.com. Your name should ideally tell what you do, where you do it, and how you do it. Covering all three is not always possible or practical. Some choose novel or quirky names. This is only a good idea if you have an extensive marketingcampaign or a site so great it will spread no matter what you call it.
Egghead definition: A domain name is an identification string that defines a realm of administrative autonomy, authority, or control on the Internet. Domain names are formed by the rules and procedures of the Domain Name System (DNS). Any name registered in the DNS is a domain name.
Domain names are used in various networking contexts and application-specific naming and addressing purposes. In general, a domain name represents an Internet Protocol (IP) resource, such as a personal computer used to access the Internet, a server computer hosting a web site, or the web site itself or any other service communicated via the Internet. –Wikipedia
Here alist of all the accredited registrars: icann.org
Where do I get a Domain?
There are many well name registrars that can help you get a domain name. You do not have to host your site with the same place you buy your domain. Many very good domain registrars don’t necessarily specialize in giving you the best hosting and development services you man need.
Here is list of some well known and respected Domain Name Providers: