Domain name extensions are on the end of top-level web structures. Each were intended for certain uses. Here are a few of the domain extensions and their original purposes:
aero- air and air transportation
.arpa -One of the original internet users- “arpa”. This extension was set exclusively to support infrastructure for the Internet Architecture Board.
.asia - Asia-Pacific region
.biz-businesses
.cat-Catalan culture
.com-commercial
.coop-co-ops
.edu- educational establishments
.gov- government entities within the United States at the federal, state, and local levels
.info -unrestricted-informational sites.
.int international
.jobs- employment
.mil U.S. military
.mobi -mobile devices
.museum- museums
.name-families- individuals
.net-network- now unrestricted
.org- organizations-now unrestricted
.pro certain professions
.tel-telephone network and the Internet (added March 2, 2007)
.travel- tourism bureaus, etc.
A generic top-level domain (gTLD) is one of the categories of top-level domains (TLDs) maintained by the Internet Assigned Numbers Authority (IANA) for use on the Internet.
(Info taken from Wikipedia).
