Each part of the domain name is a precious piece of information that’s used to identify the website in question. So, different segments of the domain help browsers to locate the web page.
Even though top-level domains and second-level domains might sound like they mark different types of domains in terms of quality, this has absolutely nothing to do with it.
A top-level domain represents the last segment of the domain name. So, it’s everything located after the final dot in the internet address. It’s also referred to as “domain extension”. Top-level domains include .com, .net, .me, .info, .org, and many more.
A second-level domain complements the top-level domain. It is a part of the domain name located left of the final dot.
So, if you look at the example of “google.com”, .com is the top-level domain, while “google” is the second-level domain.