a related question asks if there is a specific term for the voicing in Bach's Chorals:
I would have said this is the Choral.
But what I am wondering is how we name the instrumental accompaniment of the solo violin in Jesu Joy or the Bassoon Solo in BWV 140 Zion hört die Wächter singen?
I think we could call it: Ornament, Garland or Ritornell.
(As I'm planning an analysis and introduction "how to learn and teach" this arrangement/setting for piano).