TLD (Top-Level-Domain) is used to help identify the website that it belongs to. For example, this could be its purpose, geographical area where the website originates from, or the organization that owns it.
For example if you see a website that ends in .gov, then you know that that website is a government run site. If you see a web address ending in .kh, it indicates that the site is registered by either a resident or an organization operating in Cambodia. Similarly, web addresses ending in .th signify registration by residents or businesses operating in Thailand.
All TLDs are managed by the Internet Corporation for Assigned Names and Numbers, which in short is ICANN. ICANN identifies the following categories of TLDs:
- Infrastructure top-level domain (ARPA): This group consists of one domain, the Address and Routing Parameter Area. It is managed by IANA on behalf of the Internet Engineering Task Force for various purposes specified in the Request for Comments publications.
- Generic top-level domains (gTLD): Top-level domains with three or more characters.
- Restricted generic top-level domains (grTLD): These domains are managed under official ICANN accredited registrars.
- Sponsored top-level domains (sTLD): These domains are proposed and sponsored by private agencies or organizations that establish and enforce rules restricting the eligibility to use the TLD. Use is based on community theme concepts; these domains are managed under official ICANN accredited registrars.
- Country-code top-level domains (ccTLD): Two-letter domains established for countries or territories. With some historical exceptions, the code for any territory is the same as its two-letter ISO 3166 code.
- Internationalized country code top-level domains (IDN ccTLD): ccTLDs in non-Latin character sets (e.g., Arabic, Cyrillic, Hebrew, or Chinese).
- Test top-level domains (tTLD): These domains were installed under .test for testing purposes in the IDN development process; these domains are not present in the root zone.