Single-letter second-level domain

This article has multiple issues. Please help or discuss these issues on the talk page. (Learn how and when to remove these template messages) This article needs additional citations for verification. Please help by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources:  –  ·  ·  · scholar · JSTOR (January 2008) (Learn how and when to remove this template message) The topic of this article may not meet Wikipedia's general notability guideline. Please help to demonstrate the notability of the topic by citing reliable secondary sources that are independent of the topic and provide significant coverage of it beyond a mere trivial mention. If notability cannot be shown, the article is likely to be merged, redirected, or deleted. Find sources:  –  ·  ·  · scholar · JSTOR (February 2015) (Learn how and when to remove this template message) (Learn how and when to remove this template message)

Single-letter second-level domains are domain names in which the second-level domain consists of only one letter, such as x.com. In 1993, the Internet Assigned Numbers Authority (IANA) explicitly reserved all single-letter and single-digit second-level domain names in the top-level domains com, net, and org, and grandfathered those that had already been assigned. In December 2005, ICANN considered auctioning these domains.

Active single-letter domains[]

On December 1, 1993, the Internet Assigned Numbers Authority (IANA) explicitly reserved the remaining single-letter and single-digit domain names. The few domains that were already assigned were grandfathered in and continued to exist.^{[1][better source needed]}

The assigned domains in this group are the following:

Some other gTLD and ccTLD single-letter domain names are also in use, usually as shortcuts.

This list is incomplete; you can help by . (July 2017)

Many other single-letter second-level domains have been registered under country code top-level domains. The list of country code top-level domains which have been identified to allow single-letter domains are:

Single-character non-ASCII second-level domains also exist (as seen below), also known as Internationalized domain names (IDN), these domains are actually registered as their Punycode translations (which are more than a single character) for DNS purposes. ICANN oversees a process for determining registration rules that involves wide-ranging stakeholder input and assorted Working Groups. In the case of .com domains, decisions are then implemented by Verisign, the contracted backend operator for the .com Registry. The result is a list of 96,957 codepoints allowed for IDN registrations.^[5] As mentioned above, some additional domains previously-registered are "grandfathered" and remain active. Many gTLDs also allow IDN domain registration.^[6]

These 96,957 distinct IDN characters eligible for registration in .com are the essential building-blocks of languages worldwide. A single letter domain does not provide the context found in a longer string or group of words. They may appear similar to one another, or look like English / Latin characters. They sometimes are used as pictorial symbols and memorable links.

This list is incomplete; you can help by . (September 2018)