Every websites that have letter in their web address are with a domain. If you want to know what are a top-level domain which abbreviated as TLD and a second-level domain, SLD for short, and a lower level domain such as third-level domain with no official abbreviation? The first thing you must need to know is the TLD of a URL, because it is the most popular and the highest level of domains in the hierarchical Domain Name System of the Internet, and the suffix or last part of every domain name for all domains in lower than top level. Remember, the domain name is different to domain! Just try now to look at the address bar on the top of your web browser, if it is visible. But if you didn't see it, the address bar maybe hidden on your browser, just try to make it show first! Keep note that our information site is have a lot of TLDs depend on your country or territory, or on the location of the reader. For example, if you are in the Germany, our URL will be or will directed to http://developingsites.blogspot.de subdomain with .de domain! But mostly, the TLD on our domain name is .com in many other countries. So, if your browser's address bar is visible, you have a higher chance to see the address http://developingsites.blogspot.com on the address bar. That's called web address, and it is also known as URL. TLDs are divided in many groups, one is a generic top-level domain which abbreviated as gTLD, and the second is a country code top-level domain, ccTLD for short. The other TLD's groups which is insignificant to knew are not written here. The TLD is simple to analyze if it's a generic or a country code! Simply, if a TLD is not a two-letter code which is on ISO 3166-1 alpha-2 country codes and only have a single [.] dot like .org and .net, it is a generic TLD! If the letters in the TLD is an abbreviation for a country like .ph, it means that it's a ccTLD. Just remember that the ccTLD is only have two letters!
Now that you knew what a top-level domain is, this is the time to find out what's the second level which is lower than the top level of a domain, the second-level domain a domain that is directly below a TLD. For example, in promos.tk, the name promos is the SLD of the .tk but it is not a official second-level hierarchy for .tk country code TLD! In this time, you need to know that some domain name registries introduce a second-level hierarchy to a TLD that indicates the type of organization intended to register an SLD under it. For example, in the .cc domain a commercial would register under the .com.cc, while educations would register under .edu.cc domain. But there are many domains which are not official second-level hierarchies for a TLD such co.cc and cu.cc domains, those are a ccSLD of the companies who offer to register a free subdomain under their domain. SLD are also divided in many groups. So, what does the ccSLD stand for? It is country code second-level domain, a domain that is directly below a ccTLD. So, if a domain name is with the SLD under the ccTLD like .com.ph or .co.uk, it means that the domain name is registered under ccSLD! All of the ccSLD are under of a two-letter ccTLD that abbreviated a country. There are other insignificant groups of SLDs such as single-letter second-level domain like .x.com, and two-letter domain names which have two-letter name under the TLD.
These are the lower than second levels of a domain, let starts from the third-level domain a domain that is directly below a second-level domain. What is the 3rd-level domain on our domain name? The name developingsites is the 3rd domain on developingsites.blogspot.com and remember, the blogspot is the SLD. Domain name registries are doesn't have official lower than second levels' hierarchies for any domain below it! Example for the lower than 3rd-level domains in 7th.6th.5th.4rt.3rd.2st.com domain name, the name 4rt is the fourth-level domain, the 5th is the fifth-level, 6th is the sixth, and the name 7th is the seventh-level domain, etc... It's really hard to specified what the domain is, because some other articles tells slightly different on other articles. But maybe, this post is one of the right information about the domain of the internet. Keep note that if you are looking for a paid second-level domain for your domain name, check it if it's an official second-level hierarchy of the registries for the domain below it. But if you are looking for a free domain, don't expect to find a SLD which is a second-level hierarchy for a top-level domain.