Something to eat before breakfast (6)
I believe the answer is:
supper
I believe this is a double definition.
'something to eat' is the first definition.
(supper is a kind of food)
'breakfast' is the second definition.
(thesaurus)
'before' acts as a link.
(Other definitions for supper that I've seen before include "Early evening meal" , "singing for this?" , "Late repast" , "Light evening meal" , "Last meal of the day" .)