English Computing Dictionary
top-level domain
The last and most significant component of an
{Internet} {fully qualified domain name}, the part after the
last ".". For example, {host} wombat.doc.ic.ac.uk is in
top-level domain "uk" (for United Kingdom).
Every other country has its own top-level domain, including
".us" for the U.S.A. Within the .us domain, there are
subdomains for the fifty states, each generally with a name
identical to the state's postal abbreviation. These are
rarely used however. Within the .uk domain, there is a .ac.uk
subdomain for academic sites and a .co.uk domain for
commercial ones. Other top-level domains may be divided up in
similar ways.
In the US and some other countries, the following top-level
domains are used much more widely than the country code:
.com - commercial bodies
.edu - educational institutions
.gov - U. S. government
.mil - U. S. armed services
.net - network operators
.org - other organisations
Since the rapid commercialisation of the Internet in the 1990s
the ".com" domain has become particularly heavily populated
with every company trying to register its company name as a
subdomain of .com, e.g. "netscape.com" so as to make it easy
for customers to guess or remember the {URL} of the comany's
{home page}.
United Nations entities use the domain names of the countries
where they are located. The UN headquarters facility in New
York City, for example, is un.org.
Several new top-level domains are about to be added (Oct
.nom - individual people
.rec - recreational organisations
.firm - businesses such as law, accounting, engineering
.store - commercial retail companies
.ent - entertainment facilities and organisations