Staff hold a course (4)
I believe the answer is:
road
'course' is the definition.
(thesaurus)
'staff hold a' is the wordplay.
'staff' becomes 'rod' (I've seen this before**).
'hold' indicates putting letters inside.
'rod' placed around 'a' is 'ROAD'.
(Other definitions for road that I've seen before include "Way from A to B" , "public highway" , "Abbey -, Beatles album" , "Path" , "Street" .)