Bistro buy (4)
I believe the answer is:
meal
'bistro buy' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for meal that I've seen before include "Breakfast, dinner or tea" , "Breakfast, dinner or supper" , "Grain ground to powder" , "Food for male" , "Lunch or dinner, say" .)