Top woman’s court case cut short, beset by demonstration? (9)

I believe the answer is:
matriarch
'top woman's' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'court case cut short beset by demonstration?' is the wordplay.
'court case' becomes 'trial' (a trial in court).
'cut short' means to remove the last letter.
'beset by' is an insertion indicator ('beset' could historically mean 'cover').
'demonstration?' becomes 'march' (type of protest or demonstration).
'trial' with its last letter taken off is 'tria'.
'tria' going into 'march' is 'MATRIARCH'.
Can you help me to learn more?
(Other definitions for matriarch that I've seen before include "Leading lady" , "Woman dominant" , "venerable old lady" , "Dominating female" , "Powerful older woman" .)