Revolution (5)
![Ross](/clue/static/ross-mug.min.png)
I believe the answer is:
orbit
'revolution' is the definition.
(orbit is a kind of revolution)
This is all the clue.
(Other definitions for orbit that I've seen before include "Satellite's path" , "field of activity" , "Circumnavigate" , "Circuit of a planet" , "Sphere of action" .)