Cafeteria aid (4)
I believe the answer is:
tray
'cafeteria aid' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tray that I've seen before include "Flat surface for carrying things" , "Flat plate for carrying things" , "Flat board for carrying things" , "Flat carrier" , "Board for carrying items" .)