I’m sorry for any confusion, but there seems to be a misunderstanding in regards to your question about the top-level domain (TLD) STC. As per the list of Internet top-level domains maintained by the Internet Assigned Numbers Authority (IANA), which is part of the Internet Corporation for Assigned Names and Numbers (ICANN), there is no STC domain.
TLDs are the highest level of domain names of the Internet. They form the DNS root zone of the hierarchical Domain Name System. Every TLD includes many second level domains (SLDs), which are the individual domain names available to the public for registration. For instance, the TLD “com” includes SLDs like “google.com” or “iana.com”.
An example of TLD usage could be .com, which stands for commercial. It is used by mostly commercial entities, although there are no restrictions on who can register a .com domain. It’s the most recognized and most used TLD, with 53% of all TLD registration requests being for .com domains. Some examples of recognized .com domains are www.amazon.com, www.google.com, and www.facebook.com.
However, TLDs are not just limited to generic ones like .com, .org, .net, but also include country-code TLDs like .us for the United States, .uk for the United Kingdom, and .ca for Canada. These are usually used by entities that have a presence in or are associated with these countries.
There are also sponsored TLDs like .gov for U.S. government entities and .edu for post-secondary educational institutions accredited by an agency on the U.S. Department of Education’s list. Examples include www.whitehouse.gov and www.harvard.edu.
In cases where companies or organizations want a specific TLD for their branding purposes, they can apply to ICANN for a new generic TLD (gTLD). If approved, they will be able to manage and set their rules for that TLD. For instance, Google has its own .google TLD.
You can find the list of all TLDs on the IANA’s Root Zone Database webpage and more information on the ICANN’s New gTLD Program webpage.
Sources:
1. Internet Assigned Numbers Authority, Root Zone Database, Retrieved from https://data.iana.org/TLD/tlds-alpha-by-domain.txt
2. ICANN, New Generic Top-Level Domains, Retrieved from https://newgtlds.icann.org/en/program-status/delegated-strings
3. Domain Name Stat, Current Domain Name Count Statistics, Retrieved from https://domainnamestat.com/
4. ICANN, ICANN’s List of .com Domains, Retrieved from https://lookup.icann.org/lookup
5. Verisign, .COM Meaning & Origins, Retrieved from https://www.verisign.com/en\_US/domain-names/com-domain-names/about/index.xhtml
