As above, in footnotes (4)
I believe the answer is:
idem
'as above in footnotes' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for idem that I've seen before include "Ditto for a dime" , "[DOUBLE]" , "The same (as that just mentioned) (Lat.)" , "No longer employed" , "The same as just mentioned, to old Romans" .)