A TLD (top-level domain) is the final segment of a domain name, appearing after the last dot — for example, the .com in example.com. It sits at the highest labeled level of the Domain Name System (DNS) hierarchy, and the complete list of valid TLDs is coordinated by IANA on behalf of ICANN.
Every website address you type ends in a TLD. When you read wikipedia.org, the .org on the end is the top-level domain; in bbc.co.uk, the TLD is .uk. It is the single most important label in a domain name because it determines which registry controls the name and which broad category the domain belongs to.
People often call a TLD a “domain extension,” and that informal term means exactly the same thing. This guide uses the precise term, TLD, but treat the two as interchangeable whenever you see them.
Where does the TLD sit in a web address?
Domain names are read right to left, moving from the most general part to the most specific. Breaking down a full address makes the structure obvious:
| Part | Example | What it is |
|---|---|---|
| Top-level domain | .com | The extension — the highest labeled level of the DNS hierarchy. |
| Second-level domain | example | The unique name you register under the TLD. |
| Subdomain | www | An optional prefix you control once you own the domain. |
Technically there is one more level above the TLD: the root, an unnamed zone represented by a silent trailing dot (example.com.). You never type it, but it is where every DNS lookup begins. Below the root sit the TLDs, and below each TLD sit the millions of domains registered within it.
Top-level domain — the right-most label of a domain name (after the final dot), occupying the top labeled tier of the DNS naming hierarchy beneath the unnamed root.
Why does the TLD matter?
The TLD is not just decoration on the end of a name. It carries real meaning and real consequences:
- It signals identity and intent. A
.govaddress tells visitors they are on an official government site; a.iohints at a technology product; a.desuggests a German audience. - It determines who controls the namespace. Each TLD is operated by a registry (for example, Verisign runs
.com), which sets pricing and rules for that extension. - It affects availability. A name taken in
.commay be wide open in.net,.shopor a country-code TLD, giving you alternatives when your first choice is gone. - It can shape trust. Surveys repeatedly show that visitors recognize and trust familiar extensions like
.comand.orgmore readily than obscure ones.
TLD vs. domain vs. URL
A URL is the full web address including the protocol and path (https://example.com/page). The domain is the registered name within it (example.com). The TLD is just the ending of that domain (.com). Each is a smaller piece of the one before it.
What are the main types of TLD?
IANA, the body that maintains the root zone, sorts every TLD into a few categories. You will mostly encounter the first two:
| Type | Meaning | Examples | Approx. count |
|---|---|---|---|
| Generic (gTLD) | Open or themed extensions, usually global in scope. Includes legacy names and newer ones. | .com .org .net .app | ~1,200 |
| Country-code (ccTLD) | Two-letter codes tied to a country or territory under ISO 3166-1. | .us .uk .de .jp | ~300 |
| Sponsored (sTLD) | Restricted extensions run for a specific community. | .edu .gov .museum | ~14 |
| Infrastructure | Reserved for the technical plumbing of the internet. | .arpa | 1 |
If you want to go deeper on the two most common categories, see our dedicated guides on what a gTLD is and what a ccTLD is, or compare them head to head in gTLD vs ccTLD.
A quick way to spot the TLD
Find the last dot in any web address. Everything to the right of it is the TLD. In shop.example.co.uk the TLD is .uk — .co.uk together is a common second-level registration under the .uk country-code TLD.
Who decides which TLDs exist?
No single company owns the TLD system. ICANN (the Internet Corporation for Assigned Names and Numbers), a non-profit, sets the policy for which TLDs are created. Its IANA function maintains the authoritative root zone — the master file that every other DNS server on the planet ultimately trusts.
When ICANN approves a new extension, IANA delegates it: a record is added to the root pointing to the registry that will operate it. That single, coordinated root is what keeps the internet’s naming system consistent worldwide, so that .com means the same thing whether you are in Tokyo or Toronto.
★ Key takeaways
- A TLD is the last part of a domain name, after the final dot — like
.cominexample.com. - “TLD” and “domain extension” mean the same thing.
- The two types you meet most are gTLDs (generic) and ccTLDs (country-code).
- There are 1,500+ TLDs in total, coordinated by ICANN/IANA through the root zone.
Frequently asked questions
What is a TLD in simple terms?
A TLD (top-level domain) is the ending of a web address — the part after the final dot, such as .com, .org or .uk. It is the highest labeled level of the Domain Name System, and it tells the internet which broad family of domains your name belongs to.
What is the difference between a domain and a TLD?
The domain is the whole registered name, such as example.com. The TLD is only its last segment, .com. The label you choose to the left of the TLD — example — is called the second-level domain.
Is a TLD the same as a domain extension?
Yes. “Domain extension” is the everyday, informal name for a TLD. When a registrar advertises extensions like .com, .net or .store, it is selling registrations under those top-level domains.
How many TLDs exist?
More than 1,500 top-level domains are delegated in the IANA root zone: mostly generic TLDs such as .com and .shop, around 300 country-code TLDs such as .us and .de, plus a small number of sponsored, infrastructure and internationalized extensions.
Is .com a TLD?
Yes. .com is the most widely used TLD in the world. It is a generic top-level domain, originally meant for commercial organizations, but today it is open to anyone and serves as the default extension for global brands.
Sources & further reading
- IANA — Root Zone Database (authoritative list of all TLDs)
- ICANN — What does ICANN do?
- IANA — Root Zone Management
- Related: gTLD vs ccTLD, how the DNS hierarchy works, second-level vs top-level domain