Discrepancy, note, in serving of caviare (8)
I believe the answer is:
variance
'discrepancy' is the definition.
(synonyms)
'note in serving of caviare' is the wordplay.
I cannot really see how this works, but
'note' could be 'n' (abbreviation) and 'n' is present in the answer.
an anagram of 'caviare' is 'variace' which is located in the left over letters.
No letters remain.
This may be the basis of clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for variance that I've seen before include "Discrepancy, divergence" , "Difference, discrepancy" , "Dissension" , "Not the main attraction" , "disagreement" .)