What It Is:
A domain name is basically the 'address' to your website. Put a great deal of thought into selecting and then securing your domain name. Your domain name should directly reflect your business or type of business you are portraying on your website.
You can have as many domains as you want. Some people actually have created a business in regards to selling and buying domain names.
How It Works:
Whether you're accessing a Web site or sending e-mail, your computer uses a DNS server to look up the domain name you're trying to access. The proper term for this process is DNS name resolution, and you would say that the DNS server resolves the domain name to the IP address. For example, when you enter "http://webcentricom.com" in your browser, part of the network connection includes resolving the domain name "webcentricom.com" into an IP address, like 00.00.000.0, for Webcentric Communications Web servers.
You can always bypass a DNS lookup by entering 00.00.000.00 directly in your browser (give it a try). However, you're probably more likely to remember "webcentricom.com" when you want to return later. In addition, a Web site's IP address can change over time, and some sites associate multiple IP addresses with a single domain name.