Key-Systems' glossary of domain related abbreviations and terms shall help you to find your way in the complex world of domains. Learn what ccTLD stands for, what a domainer is and what web space means. Understand the link between registry, registrar, reseller and registrant and get along confidently in the domain world with new expert knowledge.

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Abbreviation for country code top level domain. Examples are .de for Germany, .fr for France and .us for the USA. The ccTLDs are geographically defined and composed of two letters.


Registry of the ccTLD .de (Germany).


Abbreviation for Domain Name System, if requested the service finds the IP address, the access number which belongs to a domain name. IP addresses are long chains of numbers. The DNS simplifies the use of the Internet by making it possible to employ the domain name instead of the IP address. The DNS is – similar to the system of phone numbers – a hierarchical name space.


An internet address, also called web address, e.g. It helps to identify computers on the Internet. The domain is part of the URL of a website (e.g. It is composed of a term (key-systems), a subsequent point (.) and a top level domain (e.g. .net). The term which prefixes the top level domain, can be divided into further levels (Subdomain). A domain describes a name space on the Internet.

Domain extension

see Top level domain


A Person who possesses a generally huge domain portfolio and who uses his domains as investment by renting them, selling them, by forwarding visitors to other web sites or the like.

Domain owner

The entity with substantial ownership rights to a domain, often referred to as the registrant. The domain owner is sometimes hidden from the public record through the use of private records or trustee services but the owner still holds responsibility for the use of the domain name.

Domain name

Synonym for domain, refers to only the character string a domain represents (e.g. and not to the technical underpinnings. Domain names are composed of a sequence of characters which are separated by points.


Abbreviation for generic top level domain, examples are .com, .info or .org. The gTLDs are defined with regards to content. .com indicates especially commercial offers on the Internet, .info refers to information offers of all kind, .org stands for organizations.


Abbreviation for Internet Assigned Numbers Authoritiy, a division of ICANN. It coordinates several of the technical conditions of the Internet. The organization operates, among other things, the Domain Name System (DNS) and regulates the allocation of IP addresses.


Abbreviation for Internet Corporation for Assigned Names and Numbers, non-profit organization, which establishes a basis for the administration of the top level domains and regulates technical aspects of the Internet as it is the supreme internet agency. Via the Domain Name System (DNS) ICANN ensures that domain names and IP addresses are allocated worldwide only once. Furthermore, ICANN coordinates the registration of gTLDs, which it has delegated to subordinate registries.


Abbreviation for Internationalized Domain Name, a domain name, which contains non-ASCII figures. This contains characters with accents, umlauts, and characters from languages which do not use the Latin alphabet.

Internet Service Provider

Abbreviation: ISP, a provider of technical services or contents which form a condition for the use or operation of internet contents and services in general.

IP address

Is used on the Internet similar to the address on an envelope for sending data from a sender to a receiver (e.g. Through the IP address, sender and receiver are definitely identifiable. An IP address can indicate one or more receivers. Additionaly, several IP addresses can be related to one computer.

Name space

An organizing principle of the information technology which is used to avoid conflicts within the allocation of names. The Domain Name System (DNS) is a hierarchical name space, which means, the DNS itself is composed of other name spaces. The single elements of a domain name, separated by a point, point to the single, hierarchical name spaces of the DNS. The domain name is always resolved from the right to the left, which means the first name space in the hierarchy is the top level domain, the second is the second level domain, the third is the third level domain and so on. In this way, the term key-systems can be used for several, distinguishable domains, e.g. for the domain or for

New TLDs

gTLDs, for which public and private sector organizations can soon to the supreme internet agency, ICANN. The new TLDs may comprise letter combinations of three to 63 characters. They can be classified into three groups. The generic gTLDs are defined by content, similar to the existing .com or .net. The geo TLDs represent cities and regions or ethnic groupgs. The third group of the new TLDs form the company and trademark TLDs. Some examples are .cam and .food for generic TLDs, .berlin or .saarland for geo TLDs, and .tui or .bmw for company and trademark TLDs.


Abbreviation for Network Information Center (usually called Registry), organization for the allocation of domains within the name space of one or more top level domains domains according to their own allocation rules. Thus a NIC also administers a part of the resources needed for the technical operation of the Domain Name System (DNS).


A person or organization which registers a domain with the responsible registry for a dedicated time period. The registrant purchases the domain either for himself or for another domain owner and is displayed in the public record.


Organization or company, which executes the registration of domains. The registrar functions as a gateway between the registrant and the registry.


Process for the purchase and technical implementation of a domain, which is executed for a registrant, either by a registry directly, a registrar, an internet service provider or a reseller.


see NIC


In general, a seller of purchased services or products. Within the process of domain registration, a reseller or a chain of several resellers can stand between the registrar and the registrant.

Second level domain

Abbreviation: SLD, viewed from the right hand side, the second character group (key-systems) within the domain name ( Domain names are composed of a sequence of characters separated by points. Those character groups match hierarchically arranged name spaces. The hierarchy of the character groups declines from right to left.


Part of a larger domain in the naming hierarchy, for example where would be the domain and would be the subdomain. This is often referred to as a third level domain or a "child domain".

Third level domain

Viewed from the right hand side, the third character group (key-systems) within the domain name ( Domain names are composed of a sequence of characters separated by points. Those character groups match hierarchically arranged name spaces. The hierarchy of the character groups declines from right to left. Sometimes refers to subdomain.

Top level domain

Abbreviation: TLD, viewed from the right hand side, the first character group (.net) and thus highest level of the domain name ( Domain names are composed of a sequence of characters separated by points. Those character groups match hierarchically arranged name spaces. The hierarchy of the character groups declines from right to left.


Abbreviation for Uniform Resource Locator, a sequence of characters, which among other things identifies and locates a web site. An example of a URL is

Web hosting

see Web space

Web space

A disk space for files on a server, which can be continuously accessed through the Internet. Internet service providers offer web space so that clients can save and publish their documents and data or internet pages there.


Request service for the information about a domain name or IP address. This information typically contains name, address and phone number of owner, administrative, billing, and technical contacts of a domain name. Other information such as creation date, expiration date and servers may also be included. Via a whois request at the responsible NIC, such data becomes accessible.

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