Distance covered by very large fruit (7)
I believe the answer is:
oranges
'fruit' is the definition.
(I've seen this before)
'distance covered by very large' is the wordplay.
'distance' becomes 'range'.
'covered by' means one lot of letters goes inside another.
'very large' becomes 'os' (abbreviation for oversize).
'range' placed within 'os' is 'ORANGES'.
(Other definitions for oranges that I've seen before include "Go snare these fruits" , "Mandarins, satsumas etc." , "Citrus fruit" , "'Mandarins, say (7)'" , "a zesty lot" .)