The main meal of the day (6)
I believe the answer is:
dinner
'the main meal of the day' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for dinner that I've seen before include "serving in 20 [MESS] ?" , "Supper" , "Eat it in the strange red inn" , "What feeds" , "Main meal of day" .)