An organization called the Internet Corporation for Assigned Names and Numbers (ICANN) controls registries that make domain extensions (or TLDs) available for purchase. ICANN assigns IP addresses, runs accreditation systems, and maintains a centralized database of all domain names and their corresponding IP addresses. As the governing body over website domains, there are two main types of domains, or TLDs, that ICANN recognizes:
Generic top-level domain (gTLD)
Generic top-level domains (gTLDs) are the most common type of domain extension used, and examples of gTLDs include .com, .net, .org, .gov and .edu. These TLDs are meant to signify the objective of a website — like commercial use (.com) or educational purposes (.edu).
Country-code top-level domain (ccTLD)
Domain names can use a ccTLD to indicate the country where a website is registered or where a company or organization conducts business. For example, .us is the ccTLD for the United States, and .ie is the ccTLD for Ireland.
While a ccTLD is meant to signify the country of a domain name, some ccTLDs, like Libya’s .ly and Tuvalu’s .tv, are chosen because of their branding value (although certain ccTLDs have limitations on who can register them).
It is also notable that these two types of domain — gTLDs and ccTLDs — can be combined, giving us common extensions like .co.uk or .com.au.