ICANN Acronyms and Terms

ICANN has hundreds of acronyms and terms, which can be confusing. We created this multilingual tool to help explain what these terms mean and facilitate your work within the ICANN community.

ICANN Acronyms and Terms

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21-40 of 62 results

Registry Request Service(RRS)

An online tool that registry operators of generic top-level domains use to submit proposals for new registry services or for material changes to existing registry services.

registry services

A set of services that registry operators of generic top-level domains (gTLD) provide under their Registry Agreements with ICANN. To modify existing registry services or offer new registry services, gTLD registry operators must obtain approval from ICANN as outlined in the Registry Services Evaluation Policy.

Registry Services Technical Evaluation Panel(RSTEP)

A team of technical experts that help evaluate the security and stability impact of requests for new registry services.

Registry System Testing(RST)

A set of tests to determine whether a registry operator has the capacity to operate a new generic top-level domain in a stable and secure manner. The RST checks critical registry functions as described in the Registry Agreement. Testing requirements vary depending on the services a registry operator supports.

Registry Transition Process(RTP)

The formal process that ICANN follows when a contracted registry operator (RO) is replaced. ICANN uses the RTP when an RO terminates its Registry Agreement and a new RO takes over. It also uses the RTP in cases where an RO changes its name or is acquired by another company.

Registry-Registrar Agreement(RRA)

A contract between a registry operator and an ICANN-accredited registrar. This contract defines the terms under which a registrar agrees to perform domain name registration services for a designated generic top-level domain.

Registry-Registrar Agreement Amendment Procedure(RRA Amendment Procedure)

The process for consideration of proposed amendments to generic top-level domain (gTLD) Registry-Registrar Agreements (RRAs) where the registry operator is required to obtain the ICANN organization's approval of such amendments. This process is designed to ensure registrar input (and public input where appropriate) before the ICANN organization approves changes to an RRA.

reputation block list(RBL)

A list of domain names, Uniform Resource Locators (URLs), or Internet Protocol (IP) addresses that are known security threats. Security systems throughout the Internet use RBLs to keep malicious or unwanted material from reaching victims. In addition to filtering out billions of incoming spam messages a day, RBLs block outgoing requests to malicious or disreputable IP addresses.

RBLs are created and maintained by commercial service providers, researchers, and public interest communities.

Request for Comments(RFC)

A document of record produced by the Internet Engineering Task Force (IETF), the Internet Research Task Force (IRTF), or the Internet Architecture Board (IAB). When the IETF develops an Internet standard, the standard is published as an RFC. The IAB, IRTF, and IETF also use RFCs to publish best practices and informational material.

reserved name

A domain name that is not available for registration in a generic top-level domain (gTLD). Reserved names include:

The Registry Agreement defines the reserved names for a gTLD. The reserved names vary according to the gTLD.


A Domain Name System (DNS) server that resolves host names on behalf of Internet users and applications (clients). Distributed throughout the Internet, a resolver performs iterative queries, starting at the root zone, to obtain the Internet Protocol (IP) address of a host computer requested by a client. Resolvers typically cache their query results so they can quickly retrieve the IP addresses for host names they have already resolved.

resource record(RR)

An entry in a zone file that enables the Domain Name System to resolve the names of host servers within a domain. Types of RRs commonly found in a zone file are:

reverse Internet Protocol(reverse IP)

A method for converting an Internet Protocol (IP) address into its corresponding domain name.

review mechanisms

Periodic assessments mandated by the ICANN Bylaws that are critical for maintaining the health of the multistakeholder model. These mechanisms help ICANN determine the effectiveness, transparency, and accountability of its organizations (Organizational Reviews) and gauge its performance with respect to key commitments and core values (Specific Reviews).

Rights holder

The person or entity that maintains a set of rights to a particular property. With respect to policy development regarding domain names, the term rightsholder often refers to a person, entity, or designee (such as a licensee or assignee) that holds intellectual property rights on a specific trademark.


The topmost, all-encompassing authority in any hierarchical naming or numbering system. Within ICANN, this term is often used to refer to the root zone in the Domain Name System.

More generally, root can refer to the central authority for a hierarchical system. In this sense, it is sometimes used to refer to the Internet Assigned Numbers Authority (IANA) functions, which maintain the root for many of the Internet’s naming and numbering systems.

The IANA functions are delivered by Public Technical Identifiers (PTI), an affiliate of ICANN.

root hints file

A file that provides the names and Internet Protocol (IP) addresses of the 13 authoritative name servers in the root zone of the Domain Name System. Recursive resolvers consult this file when resolving domain names whose IP addresses are not in local cache. The root hints file is often installed with the resolver software. It is also available from the root/files">Internet Assigned Numbers Authority website.