According to the experts

Apparently the singular of the word timpani is "kettle drum". Neither my Groves Dictionary or the Harvard Dictionary makes any distinction between one or a number of drums, but they did both point out that there was no "y" in the spelling, other than in incorrect common usage. Google didn't help, though I didn't persist with it for too long.

I guess I should have asked Giorgio yesterday.

Interestingly in the Harvard, I looked up "improvisation". There were about 8 inches of text, all devoted to historical references from the 17th century and leading up to the evolution of the cadenza. Only the very last sentence stated "An interesting revival of improvisation is in the jam session of contemporary jazz." So much for my chosen musical path.

This was only the second edition of this book, now over 30 years old. Hopefully it's been updated. To be fair, it did devote several pages to "jazz", coming up about a decade short of Ken Burns' summary.

I used to have an old music dictionary with a very disdainful, condescending and downright racist dismissal of jazz in it. I must have thrown it out.

The singular for timpani must be timpano, which as any film and food lover would remember was the object of Stanley Tucci's desire in the great film Big Night. It was an elaborate pasta dish in the shape of a drum, the ultimate achievement of Italian cuisine. That movie and Moonstruck made me want to be Italian, at least for a night. Goodfellas, not so much.