It's the name of a specific entry (I mean, at least on Earth there is only one 21st Century) so we should look for attributive use, and of course it would easily pass under those conditions. I see no harm in keep this, although the 'c' should be capitalized AFAICT. Mglovesfun (talk) 12:29, 30 December 2009 (UTC)
I am not very happy with the term "specific entity", which I read as "particular individual" as opposed to a class; "entity" ambiguously refers to both individuals and classes, and "specific" refers to the narrowness of the class.
But the main point is that this is a sum-of-parts term; it's attributive use does not rescue it from its failing to satisfy the necessary condition of not being sum-of-parts. Put differently, if a term (a) refering to one individual is (b) used attributively, and (c) is sum-of-parts, then the term should not be included; it is because of (c) that the term should not be included.
While I see no harm in keeping this term, I see no benefit in keeping it either, and this term fails CFI. --Dan Polansky 09:22, 31 December 2009 (UTC)
I agree with parts one and two of your final sentence, but not three. I think it meets CFI, but I'd rather it didn't. Mglovesfun (talk) 10:09, 31 December 2009 (UTC)
Sum of parts? I don't think so either. It's not just a century that's 21st, is it? Mglovesfun (talk) 15:36, 31 December 2009 (UTC)
It's a useful entry too, especially for translations. Tell me what good would it be to the project to delete it? Tooironic 01:57, 1 January 2010 (UTC)
As far as I can see, 18th century was only deleted because the entire content was hello. Equinox◑ 02:04, 1 January 2010 (UTC)
I have often been supporting the opinion that an entry should be kept for the sake of translations, but this doesn't deserve to be kept even because of them. Every single translation is of the form 21st+century or century+21st. It would be more useful to write an example to each language entry for "century" showing on which side of the century the ordinal belongs. And somebody might want to make an entry for Chinese 二十一 (“21”). For this, delete. --Hekaheka 06:49, 1 January 2010 (UTC)
But the translations are not just 21st + century. Some use "21.", others "XXI", and others use the equivalent word for "twenty-first". How each language "formats" a century, as it were, is not obvious, and could be quite useful for users. But this entry should be kept not just for the translations, though. Knowing exactly which years fall under a specific century can be confusing, and entries like these would be useful thus. As for the Chinese translation, you kind of stuffed up the formatting there. I will go fix that and also create an entry for 二十一. Cheers. Tooironic 23:40, 1 January 2010 (UTC)
Even if you don't buy the SoP argument, why does no other dictionary include things like this? Equinox◑ 19:38, 2 January 2010 (UTC)
I wonder for how many centuries (also decades, and years) we can attest the meanings "modern, current, up-to-date", each with the qualifier "dated" and also "old-fashioned, dated, out-of-date" also with the "dated" qualifier, but different dates.
How do other translating dictionaries (especially online ones) address these kinds of entries? Do they have entries for each century, decade, year? Do they have an appendix to which a search directs the user? We have many appendices already prepared at WP. We can supplement them with our own if they are deficient and not likely to become adequate for our purposes (whatever those may be). DCDuringTALK * Holiday Greetings! 20:24, 2 January 2010 (UTC)
I see this as comparable to names of specific cities, countries or language dialects like American English, I see no advantage in deleting it. That said, I see very few reasons to keep it. --Mglovesfun 07:18, 5 January 2010 (UTC)
A city name is not sum-of-parts, and it is a name, while "21st century" is not a name but a term. The reason why names of specific entities get special treatment in CFI is that most of them are not sum-of-parts. So not only is "21st century" sum of parts, it also is not a name, and thus is not a "name of a specific entity". By contrast, "one million three hundred thousand four hundred" is a term denoting a particular individual—a number, but should not be included as it is sum-of-parts. The term "21st century" relies for decoding on a particular numbering scheme, also known as a calendar. Compared to "the century of steam", "21st century" is straightforward to decode given a particular calendar. Otherwise, we should better include "1111" - 1. binary code for fifteen, 2. decadic code for one thousand one hundred and eleven; and other readings of the term in dependence of the choice of numeral encoding system. Also inclusion-worthy could be "11. March 2009" - how do you know which calendar you should take for reading of the term?
While I think that CFI should be taken with grain of salt, and terms that seem worthy of inclusion should be considered even outside of CFI: if a term (a) fails CFI, and (b) has nothing to recommend its inclusion, then it can be safely deleted. --Dan Polansky 12:57, 5 January 2010 (UTC)