When starting an adventure with domains, people often seek professional advice sites, blogs and forums. However, once they find the desired content, they are not always able to understand it because the terminology describing certain phenomena and mechanisms is hard to decipher. Among terms that frequently appear on domain services sites there are acronyms describing the types of domains. Here are commonly used acronyms and their meanings:
TLD stands for Top Level Domain. This means the part that concludes the web address separated from the name of the next level by a dot to the left. For example, in the extension .com.uk the top-level domain is .uk.
SLD means Second Level Domain. This is the part preceding the suffix of the TLD, also called sub-domain (in relation to the TLD). In the extension .com.uk the second-level domain is .com. On the other hand, in the address web-solutions.eu, the second-level domain is “web-solutions”. In the second example, the SLD can also be referred to as a domain name – because its function is completely different from the two-part extension in the first example.
gTLDs refers to Generic Top Level Domains – generic domains consisting of three or more letters. They usually refer to a specific area of expertise. Most gTLDs are old generic domains such as .com, .net or .info. However, since the beginning of last year, there have been over 500 new generic domains added and, ultimately, their number is expected to exceed 1 800.
ccTLDs stands for Country Code Top Level Domains – national domains consisting of two letters. This kind of extension refers to a state/country, or an independent territory. An example of a ccTLD is the .de or .cn extension. Today, almost 300 ccTLDs are in use on the Internet, among which tens of them are IDNs (extensions containing national characters not based on the Latin alphabet). The .eu domain assigned to the European Union is classified as a ccTLD, and so is the still active .su domain, established in 1990 and referring to the countries of the former Soviet Union.
geo TLD means geographic Top Level Domain. It refers to a domain related to the city, region or other geographical area, but is not equivalent with the country code domain (ccTLD). Geographical TLDs have become popular thanks to the new gTLD program, that helped launch such extensions as .nyc or .berlin. Furthermore, .asia established in 2007 is also considered as a geo TLD.
sTLD has the meaning of Sponsored Top Level Domain. Sponsored domains are created to serve a specific industry or institution and are financed by the client. STLDs have been present on the Internet for many years, but only few of them are relatively recognizable. Examples include .edu, sponsored by Educause, or .gov, sponsored by the US government.
nTLD refers to New Top Level Domain and is a collective name for all new domains created within the new gTLD program started in 2013. This category includes new domains such as gTLDs, geoTLDs or ccTLDs with non-Latin characters.
GccTLD stands for Generic Top Level Country Code Domain, or generic national domain. This combination may seem as an oxymoron, since the functions of national and generic domains seem mutually exclusive. However, some domains assigned to small countries are not very popular as country codes but appear to be attractive on global domain market. Two main reasons are behind it. Firstly, some of them, like .me or .ly, are well suited for creating domainhacks, or to serve as a meaningful element of the domain name, for instance sync.me. Secondly, such ccTLDs as .co can be deciphered as abbreviations or acronyms, for instance .co can easily be read as an abbreviated version of .com, which in turn refers to trade (commerce).
IDN means Internationalized Domain Name, that is a domain which contains national characters. It consists of Unicode characters that translate into ASCII via Punycode algorithm and become visible to the DNS (Domain Name System). IDNs swarmed the Internet as a result of the nTLD program that enabled the creation of domain names in various languages, including Arabic, Chinese and Russian. The acronym also defines a domain name that contains at least one accented character, for example À, ç, ƀ, etc.