Sebastien Pensis writes:
The .eu domain name, administered by EURid, is a unique case in the ISO 3166-1 standard and in the broader discussion of three character codes as top level domains. Because the European Union is not a country, it is not formally included in ISO 3166-1, but for practical reasons the ISO 3166/MA has the two-letter combination EU for the purpose of identifying the Eu European Union within the framework of ISO 3166-1.
Well, it is actually somewhat different (and less unique). The EU is one of the twelve exceptionally reserved alpha-2 codes. The reservation "Refers to European Union and reserved at the request of ISO 4217/MA (March 1998) for ISO 6166, Securities - International securities identification numbering system (ISIN)." <https://www.iso.org/obp/ui/#iso:code:3166:EU>. There about 50 reserved codes classified as Exceptionally, Transitionally, or Indeterminately reserved codes <http://www.iso.org/iso/country_codes_glossary.html>, therefire EU is not really special in the framework of ISO. That the ICANN board allowed to use this reserved code as a ccTLD seems the an exception that they made on their ccTLD delegation rules.
The .eu TLD exists and functions within a strict framework of EU regulations, none of which include the possibility of delegating additional European Union Top Level Domains outside of the .eu in scripts of other EU official languages. Indeed, these regulations aim to ensure a clear, unique and established web presence for the EU, the EEA and its residents.
Nitpicking Note: EEA is not an ISO code.
However in the case of three-letter combinations, the EUR ISO code is already used within the ISO 4127 currency codes and at this time,
Yes, that is why they asked for EU so they could create EUR for the EURO. For an informal overview of 4127 codes, see <https://en.wikipedia.org/wiki/ISO_4217>. The ISO home page is <http://www.iso.org/iso/home/standards/currency_codes.htm> and states: "The alphabetic code is based on another ISO standard, ISO 3166, which lists the codes for country names. The first two letters of the ISO 4217 three-letter code are the same as the code for the country name, and where possible the third letter corresponds to the first letter of the currency name." (So I got in the habit to joke about the EUR as the eu Rouble).
no ISO 3166-1 alpha-3 combination exists for the European Union.
Alpha-2 Codes reserved by the 3166 MA don't need to have an alpha-3 counterpart. jaap