A name that identifies one or more IP addresses. For example, the domain name microsoft.com represents about a dozen IP addresses. Domain names are used in URLs to identify particular Web pages. For example, in the URL http://www.blogspot.com/, the domain name is blogspot.com.
Every domain name has a suffix that indicates which top level domain (TLD) it belongs to. There are only a limited 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
# us - United States
# id - Indonesia
# it - italy
# ru - russia
# co.uk - commercial business united kingdom
Because the Internet is based on IP addresses, not domain names, every Web server requires a Domain Name System (DNS) server to translate domain names into IP addresses.