Ladder of success in the theatre (3)
I believe the answer is:
run
This clue might be a double definition.
'ladder' is the first definition.
('run' can be a synonym of 'ladder')
'success in the theatre' is the second definition.
'run' can be an answer for 'success' (run is a kind of success). I am unsure of the 'in the theatre' bit.
'of' is the link.
Can you help me to learn more?
(Other definitions for run that I've seen before include "Path made by animals" , "Control" , "Unit of score in cricket" , "Trot" , "string of performances" .)