Top-level domains (TLD) – in the hierarchy of the domain name system (DNS) the highest level after the root domain (DNS root zone). Is the reference point (from right to left) at which an Internet domain name begins.
Since each domain name consists of several parts separated by dots and written in reverse order, the top-level domain is the final part of the domain name.
For example, in the domain name in.wikipedia.org, the top-level domain is .org or .ORG because domain names are case-insensitive. Top-level domains are created to designate a territory or for use around the world for specific needs and unite groups of lower-level domains.
Each top-level domain has a coordinating body, a technical center, a domain registry, and registrar organizations. The coordinating authority is selected in the country for which the domain is intended, or from among international organizations.
Top-level domains are divided into the following groups:
- generic (general) domains (gTLDs, such as .COM, .INFO, .NET, .ORG);
- national (country) domains (ccTLDs, for example, .IN, .PK);
- internationalized domains (IDNs, such as .РФ);
- new generic (generic) domains (new gTLDs, e.g. .IO, .DETI, .TATAR).