Eggs used in Euro-elections (3)
I believe the answer is:
roe
'eggs' is the definition.
(fish eggs)
'in euro-elections' is the wordplay.
'in' indicates the answer is hidden within the clue.
'ROE' is hidden within 'euro elections'.
'used' is the link.
(Other definitions for roe that I've seen before include "Caviar" , "Food from fish" , "Hoofed animal(s)" , "Part of fish, sounds like go through water" , "If hard, eggs" .)