Cafeteria plate holder (4)
I believe the answer is:
tray
'cafeteria plate holder' 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 "Informal meal" , "Bearer" , "Flat surface for carrying things" , "Carrier for crockery etc" , "Portable carrier" .)