What is a TLD (top-level domain)?

A top-level domain (TLD) is the highest level in the internet's domain name system — the part of a web address that comes after the final dot. In example.best, the TLD is .best; in example.com, it's .com.

Domain names are read right to left, from the most general part to the most specific. The rightmost label is the TLD, the label before it is the second-level domain — the part you register — and anything further left is a subdomain the registrant controls. So in shop.example.best, .best is the TLD, example.best is the registered name, and shop is a subdomain its owner created.

Where a TLD sits in the DNS

Above every TLD is the root zone: a single authoritative list, published by IANA, of which TLDs exist and which name servers answer for each one. When a resolver looks up a name it has never seen, it asks the root where .best lives, asks those servers where example.best lives, and asks those servers for the record it actually wants. Three questions, each narrowing the search.

That hierarchy is why a TLD is not just a suffix. Adding one means being delegated a branch of the root zone and taking on the obligation to answer for every name beneath it — which is what makes operating a TLD a piece of infrastructure rather than a product listing.

The families of TLD

• Generic TLDs (gTLDs) — not tied to a country. The legacy set (.com, .org, .net) plus the hundreds of newer strings introduced through ICANN's new gTLD program, including .best.
• Country-code TLDs (ccTLDs) — two letters tied to a country or territory, like .fr or .de. Each is administered under its own national policy, which is why some, such as .ai and .io, are used far outside the country they were assigned to.
• Sponsored and community TLDs — restricted to a defined community, with eligibility rules enforced at registration, such as .edu or .museum.
• Brand TLDs — operated by a single company for its own use, delegated under ICANN's specification for a closed namespace.
• Internationalised TLDs (IDNs) — written in non-Latin scripts, encoded in the DNS through Punycode so the underlying protocol still sees ASCII.

Why the choice matters more than it used to

For most of the web's history the TLD was a habit rather than a signal: .com meant a business, and everything else was a compromise. That reading is weakening. There are now over 1,400 TLDs in the root zone, and the newer ones carry meaning the legacy set never did.

This matters most where names are read by machines. When an AI assistant resolves a request to a source, a TLD that names its category is information the model can use, not decoration. A descriptive extension states what a name is, before anyone visits it — which is the argument for a superlative TLD like .best, and the reason ICANN's 2026 round drew more than 1,600 applications.