Fragment of Home Alone set in the dining room (4)
I believe the answer is:
meal
'the dining room' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.
'fragment of home alone set' is the wordplay.
'fragment of' says the answer is hidden in the clue (I've seen this in other clues).
'MEAL' is hidden in the letters of 'home alone set'.
'in' acts as a link.
(Other definitions for meal that I've seen before include "dinner, maybe" , "Meat and two veg plus dessert, perhaps" , "Food ground up" , "Edible part of grain or pulse" , "Food taken at a particular time" .)