I’m still here, working away at the Bach Two-Part Inventions in a race against the baby clock.
And the other day, while trudging through # 5 in E min (which, okay, is kind of difficult…ugh…stay in a *&^% key, Bach!), I realized that I had never encountered ‘invention’ as a musical term anywhere except in reference to this specific collection of short pieces. It did not, as far as I knew, designate a particular form, although, loosely, there seemed to contain an exposition of a melody and then short variations on that theme following two/three different trains of thought, and then a recap at the end.
(Recaps are the Baroque equivalent of a mic drop.)