TLD
Embed This Widget
Add the script tag and a data attribute to embed this widget.
Embed via iframe for maximum compatibility.
<iframe src="https://ipfyi.com/iframe/glossary/tld/" width="420" height="400" frameborder="0" style="border:0;border-radius:10px;max-width:100%" loading="lazy"></iframe>Paste this URL in WordPress, Medium, or any oEmbed-compatible platform.
https://ipfyi.com/glossary/tld/Add a dynamic SVG badge to your README or docs.
[](https://ipfyi.com/glossary/tld/)Use the native HTML custom element.
定義
トップレベルドメイン（Top-Level Domain）。ドメイン名の最も右側のラベル（例：.com、.org、.net）。TLDはICANNが管理し、汎用TLD（gTLD）、国コードTLD（ccTLD、例：.jp、.uk）、スポンサー付きTLD（.edu、.gov）などが含まれる。
The Structure of Top-Level Domains
A Top-Level Domain is the rightmost label in a Domain NameA human-readable address (e.g., example.com) that identifies a website or service on the internet. Domain names are registered through registrars and resolved to IP addresses by the DNS system. — .com, .org, .net, .uk, .de, and so on. The Internet Assigned Numbers Authority (IANA) maintains the root zone and delegates management of each TLD to a registry operator. Verisign manages .com and .net; Afilias manages .info; country-code TLDs (ccTLDs) like .uk, .de, and .jp are managed by national organizations.
Generic, Country-Code, and Sponsored TLDs
gTLDs (generic TLDs) like .com, .org, .net, and the newer ICANN-expanded set (.app, .dev, .io, .shop) are open for registration by anyone. ccTLDs are two-letter codes assigned per ISO 3166-1 country codes and typically restricted to residents or businesses of that country, though some (like .io, .ai, .tv) have been commercialized globally. sTLDs (sponsored TLDs) like .gov, .edu, and .mil have eligibility restrictions enforced by their sponsoring organizations.
TLDs in DNS Resolution
When a recursive resolverA DNS resolution mode where the server performs the full lookup on behalf of the client, querying root, TLD, and authoritative servers in sequence until it finds the answer. Most DNS resolvers operate recursively. receives a query for a domain it doesn't know, it asks the root serversOne of 13 named root server clusters (A through M) that form the top of the DNS hierarchy. Root servers respond to queries for the root zone by directing resolvers to the appropriate TLD name servers. which authoritative serversA DNS server that holds the original, definitive DNS records for a domain zone. It provides answers directly from its zone data rather than querying other servers, serving as the source of truth for that domain. are responsible for the relevant TLD. The root zone's NS records for each TLD point to the registry's name servers, which in turn hold NS delegations for individual domains registered beneath them. This two-step delegation is fundamental to the DNS hierarchy. DNS Lookup