Presides over spread (8)
I believe the answer is:
disperse
'spread' is the definition.
('disperse' can be a synonym of 'spread')
'presides over' is the wordplay.
'over' indicates an anagram.
'presides' with letters rearranged gives 'DISPERSE'.
(Other definitions for disperse that I've seen before include "'Break up, spread out (8)'" , "Scatter, dissipate" , "Cause to separate and go in different directions" , "Scatter, break up" , "Thin out and disappear" .)