Missing only the unclued 21d. Don't want the answer (yet) but need to know: is it something an American would be very unlikely to know (like 22a, perhaps) or is it something relatively common? Thanks.
dr b I don't know if you are an American in the UK or still in the USA (the wonders of the Web !!), but you can get an online subscription to Chambers (albeit, I believe, one version out-of-date):