This page provides information about terms commonly used in the domain name industry.

2 | A | B | C | D | E | F | G | H | I | J | M | N | O | P | R | S | T | U | W


2FA – Two-factor authentication is an authentication method in which a computer user is granted access only after successfully presenting two or more evidence (or factors) to an authentication mechanism.


A Record – The A Record or A Resource Record is used to assign an IPv4 address to a DNS name. That is used to forward a domain to a corresponding IP address.

AAAA – The AAAA Record or AAAA Resource Record is used to assign an IPv6 address to a DNS name. That is used to forward a domain to a corresponding IP address.

AC – Advisory Committee

AGM – Annual General Meeting

AGP – Add Grace Period refers to the specific number of days after a domain is registered; this is frequently the first five days after registration. During this brief period, the registrar can receive credit from the registry operator for any deleted domains while the registrant can receive a refund.

ALAC – The At-Large Advisory Committee (ALAC) is the primary organizational home within ICANN for individual Internet users.

AS – AS numbers are globally unique identifiers for network operators and are used to allow them to exchange dynamic routing information. Each autonomous system is a group of Internet-connected devices having a single clearly defined routing policy. ICANN coordinates AS numbers as part of the IANA functions.

ASCII – ASCII stands for American Standard Code for Information Interchange, and it was published in 1963 and was initially used to represent characters in the English language. This character set contains the Latin alphabet in upper and lower case, the ten Arabic numerals and some punctuation marks.

ASO – The ASO advises the ICANN Board of Directors on policy issues relating to the allocation and management of Internet Protocol (IP) addresses.

Auth-Code – An Auth-Code (also called an Authorization Code, Auth-Info, or transfer code) is a code created by a registrar to help identify the domain name holder (also known as a registrant or registered name holder) of a domain name. It is used to transfer a domain name from one registrar to another.

AXFR – AXFR stands for Asynchronous Full Transfer Zone and is a method of transferring zones in the DNS to another server. This procedure is used to keep several name servers synchronous.


BC – The Business Constituency represents commercial Internet users within ICANN.

BGP – Border Gateway Protocol is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet.


CAA Record – The Certification Authority Authorization (CAA) Resource Record is used to provide domain holders with the ability to authorize certification authorities to issue a certificate for the domain. That is to prevent certificates from being issued for a domain by mistake.

ccNSO – The ccNSO or Country Code Name Supporting Organisation is a body of ICANN that advises ICANN in ccTLD domains. Many, but not all, ccTLD registries are represented in the ccNSO.

ccTLD – ccTLD stands for Country Code Top-Level-Domain or also country-specific Top-Level-Domains. There are over 200 ccTLDs, with each country assigned an abbreviation based on the ISO standard 3166. For example, the ending for the USA is .us, for France .fr and China .cn.

CNAME Record – CNAME stands for a canonical name and is a forwarding similar to the A or AAAA record. However, in contrast to these, no IP address is specified as the destination, but a different domain name.

CPH – The Contracted Parties House (CPH) is one of two houses in the GNSO, with the other being the Non-Contracted Parties House. The CPH includes the two stakeholder groups, the Registry Stakeholder Group and the Registrar Stakeholder Group.

CSG – The Commercial Stakeholders Group (CSG) represents the views of commercial Internet users and all relevant sectors of the Information and Communication Technology (ICT) industry, including but not limited to large and small business entities, business organizations, ISPs, intellectual property owners, and IP organizations.

CZDS – The Centralized Zone Data Service (CZDS) provides a centralized access point for interested parties to request access to the Zone Files provided by participating TLDs.


DANE – DNS-based Authentication of Named Entities (DANE) is an Internet security protocol to allow digital certificates, commonly used for TLS, to be bound to domain names using DNSSEC.

DNS – The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network.

DNSO – Before 2003, the Domain Name Supporting Organization (DNSO) was one of the three ICANN supporting organizations called for under the ICANN Bylaws. It has since been replaced by the Generic Names Supporting Organization (GNSO).

DNSSEC – It is a set of extensions to DNS which provide to DNS clients (resolvers) cryptographic authentication of DNS data, authenticated denial of existence, and data integrity, but not availability or confidentiality.

DoH – DNS over HTTPS (DoH) is a protocol for performing remote Domain Name System (DNS) resolution via the HTTPS protocol. A goal of the method is to increase user privacy and security by preventing eavesdropping and manipulation of DNS data by man-in-the-middle attacks by using the HTTPS protocol to encrypt the data between the DoH client and the DoH-based DNS resolver.

DoT – DNS over TLS (DoT) is a security protocol for encrypting and wrapping Domain Name System (DNS) queries and answers via the Transport Layer Security (TLS) protocol. The goal of the method is to increase user privacy and security by preventing eavesdropping and manipulation of DNS data via man-in-the-middle attacks.

DPML – Domains Protected Marks List (DPML) is a five-year block for an exact match second-level domain (SLD) across standard-priced Donuts TLDs.


EBERO – Emergency Back-End Registry Operators are organizations under three-to-five-year contracts with ICANN to provide critical registry functions, in the event of a TLD registry operator failure.

EPP – EPP stands for Extensible Provisioning Protocol and is a network protocol for communication with issuing agencies. It was completed in 2004 and is based on XML. Today, EPP is considered the standard, but it is still not supported by all registries.


FOA – Form of Authorization

FQDN – FQDN stands for Fully Qualified Domain Name and means a complete domain name with all levels. Starting with a top-level domain (e.g., com), a second-level domain (e.g., example), and then a third-level (e.g., www). Several levels can extend this. In our case, the FQDN would be


GAC – The Governmental Advisory Committee (GAC) consists of national governments and, usually, in an observer capacity, multinational governmental and treaty organizations, and public authorities, such as the ITU, UNESCO, and WIPO.

GDPR – The General Data Protection Regulation (EU) 2016/679 (GDPR) is a regulation in EU law on data protection and privacy in the European Union (EU) and the European Economic Area (EEA).

Glue Record – A glue record is required if a name server is to be entered for a domain that has the same name as the domain itself. If, for example, the name server is to be entered for the domain, the name server's IP address must also be entered.

GNSO – The GNSO or Generic Name Supporting Organisation is an organ of ICANN responsible for the development of new rules and allocation conditions for gTLDs.

GPG – GNU Privacy Guard (GnuPG or GPG) is a free-software replacement for Symantec's PGP cryptographic software suite and is compliant with RFC 4880, the IETF standards-track specification of OpenPGP. Modern versions of PGP are interoperable with GnuPG and other OpenPGP-compliant systems.

gTLD – A generic domain extension or generic Top-Level Domain (gTLD) is a domain extension that is not a country code Top Level Domain (ccTLD) like .us or .co. It defines its namespace according to a specific purpose, for example, .com (originally for commercial content), .net (for networks) or .org (for organizations).


HTTP – The Hypertext Transfer Protocol (HTTP) is an application protocol for distributed, collaborative, hypermedia information systems.


IANA – IANA (Internet Assigned Numbers Authority) is a division of ICANN responsible for the assignment of numbers and names on the Internet. In particular, its tasks include the delegation and assignment of IPv4 and IPv6 addresses.

ICANN – ICANN (Internet Corporation for Assigned Names and Numbers) was founded in 1998 in Marina del Rey, California, USA, as a non-profit organization. Since then, it has been responsible for coordinating the domain name system and assigning IP addresses.

IDN – An Internationalized Domain Name (IDN) is an Internet domain name containing at least one label displayed in a language-specific script or alphabet, such as Arabic, Chinese, Cyrillic, etc.

IETF – IETF stands for Internet Engineering Task Force and is an organization that deals with the Internet's technical development. The IETF consists of many working groups that work on improving the Internet by topic area.

IGF – The IGF was established in 2006 to provide the necessary support for the United Nations Secretary General in conducting the mandate from the World Summit on the Information Society (WSIS). The IGF serves as a platform wherein stakeholders from industry, government, and civil society can discuss Internet governance issues.

INTA – The International Trademark Association (INTA) is a global not-for-profit advocacy association of brand owners and professionals dedicated to supporting trademarks and related intellectual property to foster consumer trust, economic growth, and innovation.

ISOC – ISOC stands for Internet Society and was founded in 1992 as a non-governmental organization. ISOC supports and promotes the work of IETF, IRTF, IAB, and IESG.

ISP – An ISP is a company, which provides access to the Internet to organizations and individuals. Access services provided by ISPs may include web hosting, email, VoIP (voice over IP), and support for many other applications.

IXFR – IXFR stands for Incremental Zone Transfer and is a procedure to update zones in the DNS. The corresponding slave name servers are updated without transferring the complete zone.


JSON – JavaScript Object Notation (JSON) is an open standard file format, and data interchange format, that uses human-readable text to store and transmit data objects.


MX Record – MX stands for Mail Exchange is a DNS entry that is used exclusively for the email service. An MX Ressource record is used to specify the address of the domain's email server.


NCPH – The Non-Contracted Parties House (NCPH) is one of the two major structures making up the GNSO, with the other being the Contracted Parties House, which includes registrars and registries.

NCSG – The Non-Commercial Stakeholder Group (NCSG) is an integrated committee of the Non-Contracted Parties House within the Generic Names Supporting Organization (GNSO). It is the home within the GNSO for civil society organizations, non-profit organizations, public interest groups, and individuals who are primarily concerned with the non-commercial, public interest aspects of domain name policy.

NIC – A Network Information Center (NIC), also called registry, manages either one or more TLDs in the DNS or manages IP addresses.

NomCom – The Nominating Committee (NomCom) is an independent committee tasked with selecting key ICANN members, including the Board of Directors, the ALAC, the ccNSO Council, and the GNSO Council.

NS Record – NS Record or also Name Server Resource Record is an entry in the DNS and can either define which name server is responsible for the zone or chain several zones together. That would be the case if an NS record was stored for a subdomain.


OAuth – OAuth is an open standard for access delegation, commonly used as a way for Internet users to grant websites or applications access to their information on other sites but without giving them the passwords.


PDP – A set of formal steps, as defined in the ICANN bylaws, to guide the initiation, internal and external review, timing, and approval of policies needed to coordinate the global Internet's system of unique identifiers.

PGP – Pretty Good Privacy (PGP) is an encryption program that provides cryptographic privacy and authentication for data communication. PGP is used for signing, encrypting, and decrypting texts, emails, files, directories, whole disk partitions, and to increase the security of email communications.

PSWG – The GAC's Public Safety Working Group (PSWG) focuses on aspects of ICANN's policies and procedures that implicate public safety.

PTR Record – PTR stands for Pointer and assigns one or more hostnames to a given IP address in the DNS. It can also be considered the counterpart of A and AAAA records.


RA – The Registry Agreement (RA) is a contract that every operator of a gTLD must conclude with ICANN. This agreement regulates the rights and obligations of the registry.

RAA – The Registrar Accreditation Agreement (RAA) is a contract that every domain registrar must sign with ICANN before the registrar can accredit itself with registries to sell gTLDs directly. This agreement regulates the rights and obligations of the domain registrar.

RDAP – The Registration Data Access Protocol (RDAP) is a network protocol standardized by a working group of the Internet Engineering Task Force (IETF) 2015. The successor of the WHOIS protocol is used to search for the domain name, IP address, Autonomous System Number (ASN), and contact details of Internet resources.

RDNH – Reverse Domain Name Hijacking (RDNH) is an attempt to acquire a domain by accusing the owner of domain grabbing, i.e., by claiming that the name is yours due to a registered trademark. However, the domain was registered before the mark.

RFC – Request for Comments (RFC), in information and communications technology, is a type of text document from the technology community.

RGP – The Redemption Grace Period is an addition to ICANN's Registrar Accreditation Agreement (RAA) which allows a registrant to reclaim their domain name for a number of days after it has expired.

RIR – There are currently five regional RIRs (Regional Internet Registry) responsible for the management and allocation of IP addresses. These include RIPE (Europe), ARIN (America), APNIC (Asia-Pacific), LACNIC (Latin America), and AfriNIC (Africa). Each of these organizations is assigned its IP address ranges by IANA.

RPM – Rights Protection Mechanism is a mechanism that helps to safeguard your rights.

RR – A Resource Record is an entry in the DNS zone file.

Rr – Rr stands for a registrar, in particular a domain name registrar.

RrSG – The Registrar Stakeholder Group (RrSG) is one of several stakeholder groups within the ICANN community and is the representative body of domain name registrars.

RSSAC – The Root Server System Advisory Committee (RSSAC) is responsible for advising the ICANN community and Board on matters relating to the operation, administration, security, and integrity of the Internet's Root Server System.

Ry – Ry stands for a registry, in particular a domain name registry.

RySG – The Registry Stakeholder Group (RySG) is one of several stakeholder groups within the ICANN community and is the representative body of domain name registries.


SG – Stakeholder Group

SOA Record – SOA stands for Start of Authority Resource Record and is an entry in the DNS that contains essential information about the zone. That includes the lifetime of the zone, the serial number of the last update, and the email address of the person responsible.

SOI – Statement of Interest

SPF Record – SPF stands for Sender Policy Framework and is an entry in the DNS for sender authentication for spam protection. The receiving mail server can use the domain's SPF record to check whether the received email comes from an authorized mail server or an unauthorized server. Usually, this Resource Record is no longer used, since the same behavior is now mapped via the TXT Record.

SRS – Shared Registry System

SRV Record – Service records (SRV) are used to establish connections between a service and a hostname. When an application needs to find a specific service location, it will search for a related SRV record.

SSAC – The Security and Stability Advisory Committee advises the ICANN community and Board on matters relating to the security and integrity of the Internet's naming and address allocation systems.

SSL – Transport Layer Security (TLS), and its now-deprecated predecessor, Secure Sockets Layer (SSL), are cryptographic protocols designed to provide communications security over a computer network.


TDRP – Transfer Dispute Resolution Policy

TEAC – Transfer Emergency Action Contact

TLD – A top-level domain (TLD) is one of the domains at the highest level in the Internet's hierarchical Domain Name System, e.g., .com, .net, .org.

TMCH – The Trademark Clearinghouse (TMCH) is an essential rights protection mechanism built into ICANN's new gTLD program.

TREx – The Trademark Registry Exchange (TREx) is a new service developed by the Trademark Clearinghouse. It provides trademark holders with an additional protection layer for unregistered domain names, matching their labels, across a multitude of TLDs, by restricting the registration of these domain names in the general availability phase.

TTL – Time to live (TTL) is a mechanism that limits the lifespan or lifetime of data in a computer or network.

TXT Record – Various service providers, such as Google or Bing, require particular TXT records so that the domain in question can be entered in the Webmaster Tools, for example. Furthermore, the so-called Sender Policy Framework is now mapped via a TXT record instead of a dedicated SPF record.


UASG – The Universal Acceptance Steering Group (UASG) undertakes activities that will effectively promote the Universal Acceptance of all valid domain names and email addresses.

UDRP – The Uniform Domain-Name Dispute-Resolution Policy (UDRP) is a process established by the ICANN to resolve disputes regarding the registration of internet domain names.

URL – Uniform Resource Locator

URS – The Uniform Rapid Suspension (URS) is a process established by the ICANN to resolve disputes regarding the registration of internet domain names.


W3C – W3C stands for World Wide Web Consortium and is a committee for the standardization of techniques in the World Wide Web. Technologies standardized by the W3C include HTML, XML, CSS and SVG.

WG – Working Group

WHOIS – WHOIS is a query and response protocol widely used for querying databases that store the registered users or assignees of an Internet resource, such as a domain name, an IP address block, or an autonomous system.