Trips playing unknown stretto about middle of opera(9)T.R.E.T.S
Anagram of stretto with e (middle of opera) and x or y for the unknown? Or is it three....?
Last one before the snow brings the country to a halt.
wordplay is anagram (playing) of STRETTO and E (middle of opEra) plus Z (an 'unknown' in algebra), but I am not sure of the definition- presumably to do with trios. (I thought these were ballet shoes)
Thanks both of you. In an increasingly weirder TLS crossword anything is possible but for the Trio Terzetto to be in the public domain would be recherche in the extreme. But you have certainly put me on to something about which I knew nothing but now a little more!
Far happier with that explanation which is erudite enough. The first one still deserves some kind of award for recherchiness if you’ll pardon my French!