Taking in a fine duck, serves revolutionary course (7)
I believe the answer is:
seafood
'course' is the definition.
(type of food)
'taking in a fine duck serves revolutionary' is the wordplay.
'taking in' indicates putting letters inside.
'fine' becomes 'f' (abbreviation).
'duck' becomes 'o' (resembles zero - 'duck' in cricket).
'serves' becomes 'does' ('do' can be a synonym of 'serve').
'revolutionary' shows that the letters should be reversed in order.
'does' in reverse letter order is 'seod'.
'a'+'f'+'o'='afo'
'afo' going inside 'seod' is 'SEAFOOD'.
(Other definitions for seafood that I've seen before include "Eaten fish and shellfish" , "Such as prawns, tuna" , "The "surf" of a surf 'n' turf dish" , "Edible fish, shellfish etc from the oceans" , "Shellfish, marine fish" .)