It's kept on being secret where figures are concerned (3)
I believe the answer is:
lid
'where figures are concerned' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for lid that I've seen before include "Removable cover of a container" , "Cover from gliders" , "Hinged or removable cover as for bottle" , "Cover for box or eye" , "Kind of cover, may be hinged" .)