TLD

In short: “Top-Level Domain” — the last part of a domain, e.g. .com, .de, or .wiki.

In more detail: TLDs are managed by IANA and divided into several types: country-specific (ccTLD, e.g. .de), generic/thematic (e.g. .shop, .dev), and other special forms. Which TLDs are freely or only restrictedly registerable is regulated by the respective registry.

In Depth

TLDs form the top level directly below the root domain and can be roughly divided into categories:

• ccTLD — country-based, derived from the ISO 3166-1 alpha-2 code (.de, .fr, .jp).
• gTLD (generic) — not tied to a country, including open (.com, .net), restricted (.gov, .bank), and thematic variants (.shop, .dev).
• Geographic gTLD — regional instead of national, e.g. .berlin, .nyc (see Geographic TLD).
• Special forms — e.g. .arpa for technical infrastructure (among other things reverse DNS lookups), not intended for regular registration.

IANA (Internet Assigned Numbers Authority) maintains the official “Root Zone Database”, the authoritative directory of all existing TLDs and their respective responsible registry. New TLDs have been able to be applied for since 2012 via an elaborate, fee-based ICANN process — a single application cost around 185,000 US dollars at the launch of this programme, which has largely limited the number of applicants to large companies, cities, and specialised registries.

See also: Domain, ccTLD, Geographic TLD, Thematic TLD, Open TLD, Restricted TLD