Dinner from previous dinners (4)
I believe the answer is:
hash
'dinner from previous dinners' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for hash that I've seen before include "Keypad symbol" , "Weed" , "dish of meat and potatoes" , "reheated meat and vegetables" , "Meat dish or hallucinogen" .)