Domain

A name that recognizes one or more IP addresses. For example, the domain name microsoft.com signifies about a dozen IP addresses. Domain names are used in URLs to make out exacting Web pages. For instance, in the URL http://www.beautyofbeauty.com/index.html, the domain name is beautyofbeauty.com. All domain names have a suffix that points to which top level domain (TLD) it belongs to. There are only a restricted number of such domains.

For example:
gov - Government agencies, edu - Educational institutions,org - Organizations (nonprofit), mil – Military, com - commercial business, net - Network organizations, ca – Canada, th – Thailand.

Since the Internet is based on IP addresses, not domain names, all Web servers require a Domain Name System (DNS) server to translate domain names into IP addresses.