Coaches in theatrical parts! (6)
I believe the answer is:
stages
'coaches' is the definition.
(stage is a kind of coach)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for stages that I've seen before include "Sagest kind of play venues" , "Arranges" , "Platforms for performances" , "Theatrical platforms or portions of a journey" , "Parts of a process" .)