Central theme (5)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
motif
'central theme' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for motif that I've seen before include "Single design - theme" , "Characteristic theme" , "Theme, perhaps musical" , "Logo -- pattern" , "Recurring image in design" .)