Serial instalment (7)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
episode
'serial instalment' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for episode that I've seen before include "Bout" , "from longer work" , "Set of incidents" , "One part of a series" , "Part of TV series" .)