A domain suffix is the last part of a domain name and is often referred to as a "top-level domain" or TLD. Popular domain suffixes include ".com," ".net," and ".org," but there are dozens of domain suffixes approved by ICANN.
Each domain suffix is intended to define the type of website represented by the domain name. For example, ".com" domains are meant for commercial websites, whereas ".org" domains are to be used by organizations. However, since any entity can register domain names with these suffixes, the domain suffix does not always represent the type of website that uses the domain name. For example, many individuals and organizations register ".com" domain names for non-commercial purposes, since the ".com" domain is the most recognized.
Each country also has a unique domain suffix that is meant to be used for websites within the country. For example, Brazilian websites may use the ".br" domain suffix, Chinese websites may use the ".cn" suffix, and Australian websites may use the ".au" suffix. These country-based TLDs, sometimes referred to as "country codes," are also used to specify different versions of an international website. For example, the German home page for Google is "www.google.de" instead of "www.google.com."
Updated: May 6, 2011