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A Primer on Second Level Domains (It’s Simpler Than You Think!)

“Second level domains” is not a term you hear often, but you’ll use them all the time when browsing the web. In fact, they’re a cornerstone, which means you’ll want to know everything about them. Although, you may already have more knowledge about them than you realize.

📚 In this article, we’ll show you that second level domains are not as complex as you think with the following:

Let’s begin with bringing you up to speed on domain names as a whole.

A quick overview of domain names 📜

A domain name is a combination of several elements that direct a user to a specific website. How the mass of servers across the globe does this is beyond the scope of this post. However, in summary, each server – including that of your site – has an IP address that’s a string of numbers.

The domain name system (DNS) turns this IP address into a readable – and brandable – format, a domain name.

Domain name breakdown.

A domain name’s structure consists of three parts separated by periods. We’ll summarize the “bookends” here:

  • The subdomain, sometimes referred to as a third level domain, is a way to organize or categorize your site and sits at the front of the domain name. The www subdomain is most common, but you’ll use blog, store, mail, and plenty of others to help segment your site’s functionality or content.
  • The Top Level Domain (TLD) sits at the end of a full domain. It’s the .com, .net, .org, .io, .online portion of the web address, and there are plenty more TLDs available.

The missing part – second level domains – is something we’ll cover in the next section, and across the rest of the article.

What second level domains are 🤷🏻‍♀️

In between the subdomain (www) and the TLD (.com) is the second level domain. It represents the distinctive branding for your site – its specific name – and is the most customizable element within the full domain name.

The second level domain is significant, as it contributes to a site’s branding. It can also help you to organize and categorize your content depending on the TLD, and we’ll discuss this later. It’s the part of the domain name where you can convey your site’s identity, purpose, and even geographical location. This enables you to create meaningful, memorable, and user-friendly web addresses.

List of second level domain suggestions for "pet sitting".

Most web addresses you’ll type combine a second level domain with a TLD:,,, and arguably every other domain on the web. Here, “domainwheel”, “example”, and “revive” are all second level domains, followed by the TLD.

Overall, SLDs are central to domain name structure, and are essential where you need to define a web presence for countless sites and services across the web.

How second level domains function ⚙️

While a second level domain is the most crucial part of a domain name, you can’t simply choose one and figure the other elements out later. A domain name isn’t modular, which means you’ll need to register a TLD at the same time. The facilitator for this is a domain registrar.

There are a number about, but they all let you browse a list of potential second level domains, choose a suitable TLD, and purchase the rights to the full domain name for a set period. This often requires an annual purchase, but could stretch over two-, three-, or up to ten-year terms:

Example of domain registration term options for "".

Once you make a purchase, you’ll effectively own that domain name until you relinquish control – often through cancelling payment. This ownership provides robust legal protection with a domain name from cybersquatters and other trademark and copyright infringement – we’ll discuss this in more detail later.

Second level domains vs. third level domains 🤺

As opposed to second level domains, third level examples can be more complex and confusing. One reason is because of a number of key similarities between the two levels:

  • Subdomain structure. Both second- and third-level domains are types of subdomains, as they exist within a larger domain hierarchy.
  • Categorization. They both help users understand what type of website they’re visiting.
  • Hierarchical nature. Second- and third-level domains follow a hierarchical structure within a domain name, with the second level being closer to the TLD and the third-level domain positioned one level further down.

However, there are clear and fundamental differences between these sections of a domain name. Most importantly, second level domains let you create the primary web address for a site, whereas you can’t have a third level domain without the second level domain.

When it comes to using one or the other, you’ll use second level domains as your site’s primary branding. For instance, offers a clear and memorable way to get to the site. In contrast, is more unwieldy and hard to remember.

In a nutshell, second level domains are unique, and can convey more credibility, professionalism, and trust for a site than a third level domain. However, this doesn’t mean third level domains don’t have specific use cases. You’ll often use them for staging environments, and maybe even localization if you run multilingual content.

Third level domains in use throughout the United Kingdom (and other areas) 🇬🇧

Third level domains are more common in certain regions. Consider domain names in the United Kingdom. Most use as a typical TLD: domain example.

However, this is not technically the TLD: only .uk is the TLD here, with .co being the second level domain. This means the branding element of the domain name is essentially a subdomain. In this structure, third level domains become the way to signal a site’s location, while the second level domain signals the site’s purpose.

For instance, is a typical use case for a third level domain. Another example is that all UK government domain names use as standard.

Example of Coronavirus data UK government site.

In short, second level domains may be used in a similar way to TLDs in some regions.

A quick guide on choosing a second level domain 👩🏿‍🏫

Second level domains are clearly the centerpiece of how you brand and market your website. This is why a site like ours exists. We offer a domain name generator to help you create the most memorable and recognizable second level domains for your new site.

Domain name generator for finding second level domains.

In fact, choosing a domain name focuses almost exclusively on this aspect. Apart from branding considerations, the second level domain also has a lot of influence on your Search Engine Optimization (SEO). Domain SEO is a deep subject, and includes myriad of considerations such as the length, whether it uses hyphens, whether the domain includes numbers, and much more.

Second level domains that infringe upon trademarks or copyrighted content can, in short, lead to legal disputes. For instance, cybersquatters register domains with the intention of profiting from an associated trademark. This often results in domain disputes given the need to protect intellectual property rights and brand identity.

For example, the retail giant Walmart had to pursue legal action to obtain the domain from cybersquatters. This now transfers to the Walmart Corporate site (that uses a subdomain):

Walmart corporate site.

As such, there are processes such as the Uniform Domain-Name Dispute-Resolution Policy (UDRP) to help mitigate in these situations. Domain registrars may not have checks for malicious registrations in place, which means you should check yours using a site such as Trademark247. This can be done when choosing your domain, to make sure you’re not infringing on a trademark, and again later on to make sure nobody’s infringing on your trademark.

Trademark 247 search for the second level domain "Walgreens".

One way to stop some of the malicious issues surrounding second level domains is to opt for domain privacy. This obscures your personal details on the WHOIS database of domain names. WHO.IS information.

Privatizing the personal details attached to a second level domain is a recommended task when you register it. As such, most domain registrars offer this, albeit at different price points.

Conclusion 🎬

We often reduce it down to simply “the domain name”, but second level domains are the most important part of the whole. In most cases, it’s your brand – recognizable, rememberable, and requisite for every domain name on the web.

Even in countries like the UK, where the second level domain looks like part of the TLD, the second level domain is a key way to indicate the type of website you’re running.

Of course, you should take your time to choose the right one for your site. Not only do you need the most optimal name for your site, you should also consider the legal and privacy aspects too. Once you pair this with the right TLD, you’ll have a complete domain name to be proud of.

Now you know all about second level domains, you can use our domain name generator to find and purchase the ideal one for your site! 💪