Ring doesn't fit where one's nose is proverbially kept (10)
I believe the answer is:
grindstone
'where one's nose is proverbially kept' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'ring doesn't fit' is the wordplay.
'fit' indicates an anagram (letters fitted or arranged in a different way).
'ring'+'doesnt'='ringdoesnt'
'ringdoesnt' with letters rearranged gives 'GRINDSTONE'.
Can you help me to learn more?
(Other definitions for grindstone that I've seen before include "Disc for sharpening knives" , "hard work" , "Tool sharpener" , "sort of disc" , "nosing here?" .)