A domain name has two or more parts separated by dots and consists of
some form of an organization's name and a three letter or more suffix. For
example, the domain name for IBM is "ibm.com"; the United Nations is
"un.org." The domain name suffix is known as a generic top-level
domain (gTLD). It describes the type of organization.
Currently in use gTLDs:
.aero--For the air-transport industry
.biz--Reserved for businesses
.com--For businesses, commercial enterprises
.edu--For educational institutions and universities
.gov--Reserved for United States government agencies
.info--For all uses
.mil--For the United States military
.net--For networks; usually reserved for organizations such as Internet
.org--For non-commercial organizations.