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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A label, composed of a valid Internationalized Domain Names in Applications (IDNA) string of Unicode characters, that is in proper form and contains at least one non-ASCII character. A U-label expresses a label in the form that users expect to see it displayed in applications. U-labels are digitally represented in a Unicode encoding format such as UTF-8.

Unicode Consortium

A non-profit organization founded to develop, extend, and promote the use of the Unicode Standard, which specifies the representation of text in modern software products and standards.

Unicode is a registered trademark of Unicode, Inc. in the United States and other countries.

Unicode Standard

A universal character encoding that most modern software programs and communication protocols use to process, store, and exchange textual data. Each character in the Unicode Standard is represented by a unique integer called a code point. Besides encompassing characters from writing systems around the world, the Unicode Standard includes technical symbols, punctuation, and other characters used in written text (e.g., emojis).

The Unicode Standard is the basis for Internationalized Domain Names.

Unicode is a registered trademark of Unicode, Inc. in the United States and other countries.

Uniform Domain Name Dispute Resolution Policy(UDRP)

A policy for resolving disputes arising from alleged abusive registrations of domain names (for example, cybersquatting). The UDRP allows trademark holders to initiate expedited administrative proceedings by filing a complaint with an approved Dispute Resolution Service Provider. The UDRP is one of the Rights Protection Mechanisms that help safeguard intellectual property rights in the Domain Name System.

Uniform Rapid Suspension(URS)

An expedited administrative procedure that rights holders can initiate for certain types of domain name disputes. The URS procedure is a tool for quickly addressing clear-cut cases of trademark infringement. The URS is one of the Rights Protection Mechanisms that helps safeguard intellectual property rights in the Domain Name System.

uniform resource locator(URL)

A globally unique sequence of characters that describes the location of a specific file or resource (e.g., streaming video, software application, online service) on the Internet. The URL also identifies the protocol to use to open the specified file or resource. In the URL, https://whois.icann.org/en, https identifies the protocol to use to open the resource located at whois.icann.org/en.

unique identifier

Any identifier within a protocol that must be used in the same manner by all protocol users in order for the protocol to function correctly. Unique identifiers are recorded in authoritative registries to ensure their uniqueness and avoid usage conflicts among protocol users.

The Internet relies on many types of unique identifiers. These include domain names, Internet Protocol (IP) addresses, autonomous system numbers, and port numbers. ICANN’s technical mission involves allocating the unique identifiers that enable the proper operation of the Internet. This function is delivered by Public Technical Identifiers (PTI) as part of its contracts with ICANN to perform the Internet Assigned Numbers Authority (IANA) functions. PTI is an affiliate of ICANN.

unique identifier health

A state of general functioning of the Internet’s unique identifiers that is within nominal technical bounds in the dimensions of coherency, integrity, speed, availability, vulnerability, and resiliency.

Universal Acceptance(UA)

The principle of accepting, validating, storing, processing, and displaying domain names and email addresses correctly and consistently across all applications, devices, and systems. Universal Acceptance is a fundamental requirement for achieving a fully multilingual Internet, where Internet users around the world can navigate entirely in local languages.

Universal Acceptance Steering Group(UASG)

A community-based team working to champion Universal Acceptance as a vision for the Internet of the future. The UASG helps software developers and website owners understand how to update their systems to stay current with an evolving Domain Name System.


A serialization standard that enables Unicode characters to be transmitted over the Internet using one to four 8-bit bytes. UTF-8 (an acronym for Unicode Transformation Format 8-bit) is widely used for transmitting data over the Internet.

Unicode is a registered trademark of Unicode, Inc. in the United States and other countries.