Clinical Data – Single Letters in Blocked Puzzles
A recent discussion on this site regarding the use of ‘small’ in a wordplay to indicate the letter S highlighted the fact that while the lists of abbreviations on this site reflect the abbreviations given by Chambers, there is a disparity between these abbreviations and those which are typically allowed in blocked puzzles (which for the most part constitute a subset, but with one or two additions).
I have therefore created a new list which attempts to bring together all the codes used in blocked puzzles to indicate a single letter, including, but not limited to, abbreviations. When it comes to longer abbreviations, editors of blocked puzzles will usually accept those given by the major dictionaries (Chambers, Collins, Oxford Dictionary of English) unless they are both uncommon and non-obvious.
Codes which are likely to be accepted for some blocked puzzles but not others are shown in italics. I hope that this list will prove useful, but please leave a comment on this post if you have any observations or spot any errors. I would appreciate suggestions from readers for additional entries, particularly ones which they have seen used in a published crossword.

No idea if you’ll want to include them in the list but in the last two Guardian Prize grids I’ve encountered recipe for R (Tramp), union for U and government for G (both Vlad). I don’t know if they allow slightly more obscure ones in the prize grids – generally they’re about as hard as Friday puzzles otherwise…
Oh and in today’s Guardian we have nuclear for N… (Midway through solving the puzzle as I type!)
Thanks for this, and for R/U/G. It appears that any single-letter abbreviation that appears in Chambers is fair game in the Graun. I’m not aware that setters for that series receive a list of permitted single-letter abbreviations, but if anyone knows otherwise I’d very much like to know. I can’t see any purpose in adding those four to the blocked puzzle list, as it was intended to reflect the restricted palette typically available to blocked puzzle setters, but I will add a note to the introductory text.
Was “student” for “L” a deliberate omission? I realise it’s possibly akin to “tory” for C, but I have come across it in Guardian, FT and Indie puzzles…
Thanks, Anon
Personally, I think it’s significantly worse than ‘Tory’ for C, but when it comes to this list my view on validity is irrelevant. It’s clearly something that’s allowed in most of the back-pagers, and as of today it’s in the list, whether I like it or not!
Hi Dr Clue,
Imogen’s recent prize puzzle in the Guardian had Ohio for O [OCCIPUT – Still up in Ohio canal? Head back (7)]
It’s in your other list of common abbreviations but perhaps worth adding to this one? (I wasted some solving time trying to fit OH in there!)
Hi Anon
Thanks for that. I have a feeling that only the Guardian would allow it, but that’s sufficient to justify its inclusion. I’ve added it to the ‘waiting list’ ready for the next update – there are close to 20 pending changes across the board, so I’m planning to deal with them next month.
Today, Everyman offers us D for ‘drive’. I can only find support in “Collins online” for an American-English reference to what might appear on an automatic gear stick.
Thanks, Jay
Hmm, I’m afraid Everyman isn’t what it once was. Suffice to say that I shan’t be adding ‘drive’ for D to the list.
I note S for Stokes appears in one of today’s blocked puzzles.
Supported by Chambers, but I couldn’t see it in the list here.
Thanks, Jay. What crossword did it appear in?
Today’s Guardian.
5d. Give a boost to Stokes with three overs (4,2)
Thanks for that.
Firstly, my apologies that your comment got blocked as spam. The word ‘boost’ was at one time very popular among spammers (you may be able to guess what sort of product was being promoted!), but it doesn’t seem to appear very often these days, so I’ve now removed it from the ‘block’ list.
That’s interesting about ‘Stokes’. I have never seen a list of abbreviations that are allowed in Guardian puzzles and would be very interested to know if such a thing exists. Allowing ‘stokes’ would make the Guardian an outlier in terms of the back pagers, so I will add it as a ‘discretion advised’ abbreviation.
Hereabouts, non-weekend days for university schedules are represented by the letters M T W R F. Is that so elsewhere (outside North America, and outside institutions of higher education)?
How interesting – that’s a new one on me. A quick google suggests that it is indeed limited to the spheres which you mention, but others may know differently. R for Thursday seems a bit, well, random, given that ‘Thursday’ has an H in position 2 and no other day has that letter in its name. Do you know why R was chosen?
Having spent so much time in schools–giving and receiving–I have internalised ‘MTWRF’. I have seen ‘H’ for “Thursday”, but that usage is far less common. As for the reason behind ‘R’ (and generally not ‘H’) for “Thursday”: for classes that meet on Tuesdays and Thursdays, a notation of ‘TR’ would indicate the two days, whereas ‘TH’ would suggest “Thursday” alone.
Ahh, thank you – I knew there’d be a good reason!
A useful list. I think it might be worth including “by” for X, as this is fairly well-established. As I’ve mentioned to you before, I think it’s extraordinary that Y and N for “yes” and “no” are not regarded as standard abbreviations.
Thanks, Richard – agreed, I’ve added ‘by’ = X as being allowed by some puzzles. Personally, I feel it ought to be universally allowed, but then so ought Y/N and L/E/N, at the very least. Do these editors never fill in questionnaires or wire up electrical plugs?
As far as this list is concerned, I will add any suggested ‘codes’ that seem potentially acceptable or have been seen in published puzzles, since they are likely to reappear; when it comes to the more outré ones, setters can decide whether they want to risk them or not! All suggestions will be welcomed.
In the spirit of “horseshoe” for ‘U’, and rugby goalposts for ‘H’–noting that I find the former reasonable and the latter not–what of “hook” for ‘J’ and “fork” for ‘Y’? Neither of those is my invention, but I have encountered and used both.
[And Chambers not including abbreviations for standard clothing sizes is ridiculous.]
Thanks, Dr Daniel – I will add those to the italicized group. In curated puzzles, I would suggest that (like ‘horseshoe’ and ‘notch’) they might or might not be accepted depending on whether the editor has enjoyed a good breakfast.
I completely agree about the clothing sizes. The abbreviations in Chambers, particularly the single-letter ones, require a complete overhaul. I question whether the editors know the reason for the inclusion of some, such as ‘d’ for ‘deserted’. In Admiral William Smyth’s The Sailor’s Word-book (a remarkable piece of work) he writes that in the ‘Complete Book’ (the book which contained the particulars of every waged person on board a ship) “D means dead or deserted; Dsq., discharged from the service, or into another ship.” Army deserters were branded – or later, tattooed – with a ‘D’, but that stood for ‘deserter’ rather than ‘deserted’. Time, I think, that abbreviation was Dsq.