Second-Level Domain

What Does Second-Level Domain Mean?

A second-level domain is a specific part of a website, page domain name or URL address that complements a top-level domain. One of the easiest ways to define a second-level domain is that it consists of that portion of the domain name to the left of the “.com” or other similar extension, which is called a top-level domain. Analysis of the top-level and second-level domains helps to analyze a URL or page address.


Techopedia Explains Second-Level Domain

In a very general sense, a second-level domain is often thought of as the “name” of the domain. The top-level domain, which is an extension such as “.com,” is fairly generic. Although it is the controlling address feature, it does not help to distinguish a site from others. The second-level domain often plays this role; for example, in a domain name like “,” the word “google,” as the second-level domain, is where domain holders put the brand name, project name, organization name or other familiar identifier for users.

In addition to these common second-level domains, there is also the idea of a country code second-level domain (ccSLD). Here, the second-level domain is actually to the right of the decimal delineator; for example, in a domain like “,” the country code top-level domain is the “uk” portion, whereas the ccSLD is the “.co.”


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Margaret Rouse

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.