Top Level Domain and more: The Big Domain Glossary (Part 1)

If you want to register a domain, there will definitely be a lot of terms and shortcuts you might not know. This is why we created a glossary that lists the most important terms regarding domain hosting. So let´s start with the basics: what is a domain and how do the subcategories differ?


In today’s times it is quite normal for companies and individuals to have a personal internet presence. In order for a web presence to be found online, it has to be connected to a named domain address, for example This domain name primarily serves usability, since words are easier to remember than strings of numbers. On the backend, computers assign every website a special sequence of digits, called an IP address.

Through the Domain Name System (DNS), a domain´s components are strictly hierarchically divided from left to right and consist of the Top Level Domain (TLD), Second Level Domain (SLD) and Third Level Domain (Subdomain)

Top Level Domain (TLD)

A Top Level Domain is the last part of a domain name, the section behind the dot. Domain endings can be divided into three groups. First, there are the general or generic domain endings (gTLD), for example .com, .org. or .net. Second are country-specific Top Level Domains. More than 200 country codes belong to ccTLDs (Country Code Top Level Domains) such as .us (United States), .fr (France), and .es (Spain). Additionally, the new Top Level Domains (nTLDs) have been made available in stages since 2013. These include short and easy-to-remember domain endings such as .xyz, .shop, or .newyork.

Second Level Domain (SLD)

The Second Level Domain gives a website its unique name before the TLD, for example the name of an institution or company ( Because of this characterizing function, SLDs have both name and trademark protection.

Third Level Domain

The Third Level Domain is also referred to as a Subdomain. It gives websites the opportunity to be organized logically and structurally. This can be useful if branches, departments, sectors or language version should be summarized under a superordinate website. Some PROGRAMAGE examples for the use of Third Level Domains include:

Did you know? The probably most commonly used subdomain is the internet standard “www” (World Wide Web).

Country Code TLD

ccTLDs refer to country as well as region and consist of a two letter code, for example .de (Germany), .fr (France), .es (Spain), .it (Italy), .uk (United Kingdom), .us (United States) und .mx (Mexico). There are more than 200 country codes available.

Generic TLD

Roughly 20 generic Top Level Domains (gTLD) have a length of three or more letters. They are divided into sponsored (sTLD) and unsponsored Top Level Domains (uTLD). Sponsored means that the TLD is controlled, proposed and financed by a company or organization. For example, .gov and .mil are exclusively for the US government and US military institutions.

More widely known are the unsponsored generic TLDs, which are administrated by the ICANN and the Internet Society. They include .com, which is the most registered TLD in the world with about 127 million registrations.

CNOBI Domains

This acronym consists of the initial letters of the five generic domain endings .com, .net, .org, .biz and .info. They are specialized in certain application areas, but can also be registered without restrictions.

.com (commercial): for companies and commercial enterprises
.net (network): for (computer) networks
.org (organization): for non-profit or commercial organizations
.biz (business): for websites with a business background (e.g. companies, freelancer or professionals)
.info (information) for website information


“Old” Top Level Domains (gTLDs and ccTLDs) are limited in variety since many are already registered. Due to this, new Top Level Domains (nTLDs) have been introduced. These new domain endings offer users the chance to register short and concise web addresses, which also have a high recognition value. There are for example nTLDs with a local reference (.nyc, .miami, .vegas), for activities and interests (.photography, .sport, .cloud) as well as for special branches (.restaurant, .construction, .car).

In part 2 of this series, we’ll tell you everything you need to know about the domain name system (DNS), URLs and root servers.