Joseph Peterson suggests a new term for what we frequently call “second level domains”…because second level isn’t always accurate.
Last month I suggested the term nTLD to categorize certain domain names. This month I’d like to suggest a name for domain names that you and I can register at a domain name registrar:
FLD – Short for “Free Level Domain”.
This one may not catch on, but I’ve been using it internally as a variable and field within all my databases for quite some time. The meaning is quite familiar; only the word and the precise application are a bit new. In common parlance, this is what many people mean when they say “SLD”.
What’s wrong with “SLD” then? Well, literally “SLD” stands for “second level domain”. It’s the string immediately to the left of the TLD. So if we’re looking at Facebook.com, then “com” is the TLD, followed by “Facebook” as SLD. So far, so good …
But what about extensions such as .CO.UK, .COM.MX, .CO.IN, and .COM.AU? Take a look at Facebook.com.au. Here the TLD is not .COM.AU, which is what I term an “extension”. Rather, the TLD is “au” – whatever falls to the right of the rightmost dot. When we looked at Facebook.com, the SLD was “Facebook”. Yet that isn’t true of Facebook.com.au. Instead, its SLD is “com” – the string immediately to the left of the rightmost dot. The rule for locating the SLD remains the same for both Facebook.com and Facebook.com.au, but the results are utterly different.
When domainers speak of SLDs, they typically mean whatever string they’re free to register – something on the far left of their chosen extension. And it’s not just amateur domainers who use “SLD” in this way. Estibot (the auto-appraisal system) has long had a column for “SLD” denoting this leftmost string. Likewise, DomainTools.com defines “SLD” in a way that could lead toward this misunderstanding.
Technically, this sense of “SLD” as the leftmost string we choose to register is simply incorrect. It’s in conflict with the legitimate use of “SLD” to differentiate these New Zealand extensions: .CO.NZ, .KIWI.NZ, AC.NZ, .GEN.NZ, .MIL.NZ, GOVT.NZ, .MAORI.NZ, and so forth. All of them are built on the .NZ TLD using various SLD strings; and what the registrant is permitted to choose would be the third level domain (3LD). Even for those who are content with a loose misapplicationof “SLD”, there remains this dilemma: In the case of Facebook.co.nz, we cannot simultaneously refer to both “co” and “facebook” as the “SLD”. It doesn’t matter that 1 is correct and the other incorrect. What does matter is that we’re confronted with 2 different things but only 1 word. We need a separate term.
It’s not satisfying merely to concede that the “Facebook” in Facebook.com is an SLD whereas the “Facebook” in Facebook.co.uk is a third level domain (3LD). That explains the difference properly, but it neglects the similarity. Yes, both happen to be the same string. But those 2 “Facebook” strings are fundamentally identical with the “GoDaddy” in GoDaddy.com and to the “BBC” in BBC.co.uk. All of these can be defined as the leftmost string that is freely selected out of nearly infinite options by the registrant. That’s what’s important.
ICANN Wiki’s definition of “SLD” explicitly discusses the surrounding confusion, as I have done. Indeed, the governing body of the internet offers a weak solution in the form of this sentence:
In these circumstances, the third level domain is sometimes referred to as a functional SLD.
The phrase “functional SLD” is disappointing and inadequate. For one thing, “functional SLD” is much too long to ever enter circulation. Many domain professionals eat, breathe, and sleep this concept; it’s half of everything we buy, sell, analyze, and debate. We’d feel ridiculous reading / writing “functional SLD” dozens of times per day. It’s also a mistake to pretend that these leftmost strings are (like SLDs) defined from the right when they are obviously defined from the left. The “Facebook” in Facebook.co.nz is not “functionally” like the “co” in this same domain – not in any sense.
To my knowledge, nobody has introduced a viable term for this leftmost, registrable string. Since, I’ve been privately using “FLD” in this sense for a long time, writing it hundreds of times a day in database queries and procedures, I may as well introduce it publicly – if only so that I can begin saying it in public myself.
As I mentioned above, “FLD” stands for “free level domain” – the idea being that we are free to improvise this leftmost string when registering or even imagining a domain. I’m free to treat AsbestosFlavor.net and AsbestosFlavor.co.uk as realistic hypothetical domains, and I’d be free to register that same FLD in either extension – in one case as an SLD and in the other as a 3LD. For those of you who enjoy ICANN’s cop-out phrase, “functional SLD”, this “FLD” acronym can stand for “functional” as well.
All of this may strike some people as pedantic and unnecessary. But the term really aids discussion, and I’ve felt hobbled by not using it. Assuming people recognize “FLD”, then someone could write the following sentence:
Please submit domains in non-SLD ccTLD extensions having single-word FLDs in the language of the country.
That would mean that this person is looking for country code extensions like .MX or .IN but that he isn’t interested in SLD extensions such as .COM.MX and .CO.IN. In the same breath, he could specify the type of registrant-defined leftmost string that interests him: single words, native language.
When discussing privately leased subdomains such as Lawyer.co.com, I would recommend defining “FLD” from the perspective of the buyer / lessee. In that example, someone originally registered the FLD “co” as an SLD in the TLD .com. Later they began marketing their domain itself as an extension, leasing third level subdomains (3LDs). Now that those 3LDs are available to buy, it simplifies things if we consider them FLDs as we would consider the same strings in .CO.UK or .COM.MX.
Sometimes the SLD and FLD coincide, and sometimes they don’t. Without a generally observed distinction between the SLD and FLD portion of a domain (whatever you may call it), communication tends to be less exact; and domainers tend to appear ignorant of what an SLD actually is. Precision of this kind is especially important when programming domain-related software or writing domain legal policies. Nevertheless, I see no reason why “FLD” couldn’t be used more widely than just me, since domainers refer to this underlying meaning every day by means of a term that actually means something else. After all, “FLD” is every bit as simple to say as the erroneous “SLD”.
3LD – Unlike TLDs and SLDs, third level domains such as the “Facebook” in Facebook.com.au have no recognized abbreviation. We cannot re-use “TLD”, which is what we’d get if “third” were replaced by “T”. So we may as well write “3LD”, right? I’ve already been compelled to write out “third level domain” multiple times in the paragraphs above; so clearly a shorthand is useful. Now I can say this more clearly:
In a TLD extension, the FLD will be registered as an SLD; whereas in an SLD extension, the FLD will be found in the 3LD.
And if you were to register AsbestosFlavor.co.uk and begin leasing subdomains, then we could register the FLD “delicious” as a 4LD in the form of delicious.AsbestosFlavor.co.uk.