A domain name is a recognition label that describes a area of administrative self-sufficiency, power, or else control in the Internet, supported on the Domain Name System (DNS).

Domain names are mainly used in different networking contexts as well as application-specific naming with addressing purposes. They are prearranged in secondary levels (subdomains) of the DNS rootdomain, which is unknown. The first-level set of domain names are the top-level domains (TLDs), with the general top-level domains (gTLDs), for example the prominent domains com,net as well as org, and the countryside code top-level domains (ccTLDs). Beneath these top-level domains in the DNS hierarchy are the second-level as well as third-level domain names that are normally open for reservation by end-users that wish to hook up local area networks to the Internet, run web sites, or else make other openly accessible Internet resources. The registration of these domain names is generally administered by domain name registrars who trade their services to the public.

Individual Internet host computers make use of domain names as host identifiers, or else hostnames. Hostnames are the leaf labels in the domain name system generally without additional secondary domain name space. Hostnames emerge as a part in Uniform Resource Locators (URLs) for Internet resources for instance web sites (e.g., en.wikipedia.org).

Domain names are also used as straightforward recognition labels to specify ownership or else control of a resource. Such examples are the realm identifiers used in the Session Initiation Protocol (SIP), the DomainKeys used to confirm the DNS domains in e-mail systems, as well as in numerous other Uniform Resource Identifiers (URIs).

A significant purpose of domain names is to offer simply familiar as well as memorizable names to numerically addressed Internet resources. This abstraction enables some resource (e.g., website) to be moved to an unusual physical place in the address topology of the network, worldwide or else locally in an intranet. Such a move frequently requires changing the IP address of a resource with the corresponding translation of this IP address to as well as from its domain name.

Domain names are frequently referred to simply as domains as well as domain name registrants are often referred to as domain owners, even though domain name registration with a registrar does not present any authorized ownership of the domain name, only an limited right of use.

This article mainly discusses the group of domain names that are presented by domain name registrars for registration by the public. The Domain Name System article discusses the technical facilities with infrastructure of the domain name space as well as the hostname article deals with exact details regarding the use of domain names as identifiers of network hosts.