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Before 1983, visiting a host on a network required typing in its IP address. Fortunately, the domain name system (DNS) was invented to allow numerical IP addresses to be identified with domain names. So now, instead of having to remember a long sequence of numbers like, you only have to remember The definition of a domain extension is the top-level part of a domain name, like .com or .net.

It’s easy to forget that each domain extension is intended to be used for a specific purpose when everyone is using .com for whatever they please. But you might be surprised to find out that a lot of domain extensions have registration restrictions and are still used for their intended purposes.

Or maybe you want to find out which unique domain extensions are unrestricted and can be used along with your killer domain name 6 Domain Generators To Find That Killer Domain Name 6 Domain Generators To Find That Killer Domain Name Read More to make your website stand out. Let’s take a look at the history of domain extensions, which ones are restricted and which ones aren’t, and what specific use each is intended for.

History of Domain Extensions

In 1984, the Internet Assigned Numbers Authority (IANA) established the first six domain extensions: .com, .edu, .gov, .mil, .org, and .net.  Shortly after, the first two-character country code domain extensions (like .uk and .us) were established. In 1988, .int was also introduced.

definition of domain extensionsIt wasn’t until after the Internet Corporation for Assigned Names and Numbers (ICANN) was created in 1998 that any new domain extensions (besides country code extensions) came into use. ICANN has an agreement with the United States Department of Commerce and now operates IANA.

After an application period, seven new domain extensions were introduced in 2000: .aero, .biz, .coop, .info, .museum, .name, and .pro. Throughout 2005 and 2007, .cat, .jobs, .mobi, .tel, .travel, and .asia were also established.


New domain extensions are sure to come. Just last month, the first “internationalized” domain extensions were established. These internationalized domain extensions are the first to not use Latin characters (three of them use Arabic characters and one uses Cyrillic).

Read on to find out the different categories that domain extensions are grouped under and the specific uses for all of the domain extensions mentioned above.

Types of Domain Extensions

There are two main types of domain extensions: country code and generic (which is further subdivided into sponsored and unsponsored).

Country code extensions are two-character domain extensions for countries, sovereign states, and territories. Many country code extensions have second-level subdomains, like the .co in

Generic domain extensions include all of the other domain extensions, like .com, .edu, and .biz. Sponsored extensions, like .aero, .coop, and .museum, are managed by an organization that is in charge of the policies regarding their registration. Unsponsored extensions are simply managed by ICANN.

definition of domain extensions

All domain extensions are also either restricted or unrestricted. To register a domain name with a restricted domain extension, you have to meet certain requirements. For example, only accredited educational institutions are eligible to register a domain with a .edu extension. Many country code domain extensions are also restricted and can only be registered by citizens or residents of the country that the extension refers to.

Unrestricted domain extensions, like .com, .org, and .net, can be registered by anyone. Some country code domain extensions are unrestricted, which has resulted in the registration of “domain hacks” that create a word using the domain extension., for example, uses the United States country code .us to form the word “delicious.”

A List of Modern Domain Extensions

Here is an alphabetical list of all generic domain extensions and their specific uses:

  • .aero – Used in the aviation industry.
  • .asia – Used in Asia.
  • .biz – Used by businesses.
  • .cat – Used for Catalan-language websites.
  • .com – Intended for use by commercial entities, but it is unrestricted.
  • .coop – Used by cooperatives.
  • .edu – Used by post-secondary educational institutions.
  • .gov – Used by United States government entities.
  • .info – Intended for use by “informative” websites, but it is unrestricted.
  • .int – Used by international, treaty-based organizations.
  • .jobs – Used by websites dealing with employment.
  • .mil – Used by the United States military.
  • .mobi – Used by websites optimized for access on mobile devices.
  • .museum – Used by museums.
  • .name – Used by individuals.
  • .net – Intended for network infrastructure use, but it is unrestricted.
  • .org – Intended for use by organizations, but it is unrestricted.
  • .pro – Used by licensed professionals, including those in the legal, accounting, and medical professions.
  • .tel – Used to store and publish contact information.
  • .travel – Used by entities in the travel industry.

New domain extensions are constantly being proposed and debated. Many want more geography-based domain extensions like .asia. To that end, domain extensions like .london, .nyc, and .quebec have been proposed.

There has also been widespread support for the domain extension .kids, which would be used by websites designed for children. Contrarily, the .xxx domain extension has just recently been approved after years of debate, and it’s intended to be used by adult entertainment websites in the near future.

What domain extensions do you want to see in the future?

Image Credit: binsurf

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  1. Kit
    January 12, 2016 at 10:04 pm

    Needs to be updated to include .win extension. Not sure where that one is from but I have been seeing it a lot, especially in my spam folder.

  2. Aibek
    July 6, 2010 at 12:45 pm

    wow, had no idea about many of those specific extensions. nice read.

    • traver
      January 29, 2015 at 10:29 pm

      wow,now I can know......

  3. Tony
    July 6, 2010 at 1:57 am

    Very good post. I find this post more useful.