Ring for a sandwich (5)
I believe the answer is:
round
I believe this clue is a double definition.
'ring' is the first definition.
(synonyms)
'for a sandwich' is the second definition.
(as in a round of sandwiches)
(Other definitions for round that I've seen before include "Drinks order" , "Description of Tweedledum" , "Number of drinks bought together" , "Circular - spherical" , "rung of the ladder" .)