What is a Top Level Domain (TLD)?

You may or may not know this, but there is a hierarchical structure to domain names. It is actually the very heart of DNS. Different levels are assigned to distinct DNS servers, including the top-level domain server, to get end users to their online destinations. 

What is DNS?

We have many resources that adequately define DNS and its working parts, but for the sake of this piece, we’ll give you the basics to help you better understand what a top-level domain (TLD) is. The Domain Name System (DNS) is a decentralized naming system for the internet and functions much like a modern-day, online phonebook for domains. Without it, you would have to memorize all of the IP addresses that are tied to websites. Plus, to have to remember their various pages on top of that—you would have to remember many numbers just to navigate through one website. With DNS being a pivotal part of the internet, you only have to enter the domain name. 

How DNS Works

When a domain is entered into a browser, the query goes through a systematic process before the end user is connected to the website. The process is laid out in a hierarchical structure so that the domain is located and presented back quickly and seamlessly. DNS handles all the heavy lifting for an optimal end-user experience. For a thorough breakdown of DNS and how it works, see our What is DNS? resource. 

DNS Hierarchy 

When searching for a website, the query will typically go through four servers to locate the resource. A URL consists of different segments that need to be resolved by different servers. The query will first visit and remain at a recursive server. If the information in the recursive server’s cache, it will return the website to the user. If not, it will send and receive data related to the query to three authoritative servers until all the necessary information is obtained to deliver the proper domain to the user: root, TLD, and authoritative (DNS). These authoritative nameservers are the only ones that give answers related to the query, so each resolves for a different part of the domain.   

The first authoritative nameserver is the root nameserver that resolves for that invisible dot at the end of a URL (constellix.com.).Yes, there is a dot at the end of URLs. Try it out for fun and you will find that you will be connected to the same website whether you add it or not. This server will reply with information that it may already have in its cache or more often than not, refer the recursive server to the TLD nameserver to continue its quest. 

Top Level Domain

Here is where we get to the main reason you visited this resource. This is the part of the query journey where the TLD nameserver receives the information request from the recursive server. The TLD is anchored to the root domain. For example, in constellix.com, that would be the .com segment of the root domain. 

There are two main categories in which TLDs are classified: generic TLDs and country-specific TLDs. Generics are the most popular and are usually the ones that are available for registration for company-specific trademarks. 

Top-Level Domain Examples: 

TLDs are commonly referred to as domain suffixes and there are a lot of them. Some are reserved for unique purposes and are quite distinguishable from the standard TLDs. For example, educational institutions are assigned .edu, U.S. government agencies are assigned .gov, and those designated for military use .mil. 

TLD List

Here are some of the most popular ones:

• .com
• .net
• .gov
• .mil
• .org
• .edu
• .biz

Did you know? The now common .com TLD was initially established for commercial use only. With the growth and evolution of the internet, this restriction was lifted. 

Once the TLD is determined, the authoritative nameserver (DNS nameserver) is the decisive server that the query reaches before being sent back to the recursive with the final answer needed for the IP address to be fully resolved. The domain that was originally queried is then converted into the corresponding IP address and delivered back to the end user.  

Once the TLD is determined, it refers the recursive to the authoritative nameserver (DNS nameserver). This is the decisive nameserver that the query reaches before being sent back to the recursive with the final answer needed for the IP address to be fully resolved. The domain that was originally queried is then converted into the corresponding IP address and delivered back to the end user. In rare instances, a final answer is not received and the query process repeats.  

Fun Fact: The first TLDs were .com  and .org and they were established in the 1980s when the first domains were in development. 

TLD Meaning in a Nutshell

TLD (top-level domain) is the segment of the root domain that assists in recognizing the country of origin and the website’s purpose or objective (government, education, etc.). Some of the most used examples of TLD are .com, .gov, .edu, and .org. The TLD nameservers play a crucial role in the query journey. 

Related resources:

Authoritative and Recursive DNS: What’s the Difference?

What is Primary DNS?

What is DNS Propagation?