I was looking for the musical term to describe a song where one line was started by the lead singer and repeated by the backup or congregation.  The initial term coming to mind was counterpoint, but once I found this glossary of terms, discovered that was incorrect as the counterpoint was where two different melodies played over each other.  So, I didn’t find the term desired, but did find a good glossary. Some of the terms were well known, some I had tickle my ears at some point, and a few were in the category of, “well, that’s interesting.”