Choreographer Bob (5)
I believe the answer is:
fosse
'choreographer bob' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for fosse that I've seen before include "-- Way, Roman road" , "Ditch or moat" , "Fortification ditch" , "Long, narrow trench or excavation" , "Fortified moat" .)