European agreed to reveal studies (4)
I believe the answer is:
eyes
'studies' is the definition.
The definition and answer can be both man-made objects as well as being plural nouns.
Maybe there's an association between them I don't understand?
'european agreed' is the wordplay.
'european' becomes 'E' (abbreviation e.g. EU).
'agreed' becomes 'yes' ('agreed' can mean 'yes').
'e'+'yes'='EYES'
'to reveal' acts as a link.
Can you help me to learn more?
(Other definitions for eyes that I've seen before include "''Drink to me only with thine ...'' (Johnson)" , "Storm centres" , "Blemishes on potatoes" , "Views" , "Peepers" .)