There's a case for it in a canteen (7)
I believe the answer is:
cutlery
'canteen' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I don't see?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for cutlery that I've seen before include "Eating irons" , "Eating utensils" , "Knives, forks, etc" , "Knives, forks and spoons" , "Eating implements" .)