The day before a girl is found (3)
I believe the answer is:
'the day before' is the definition.
(eve is the night before something)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for eve that I've seen before include "See 27" , "Previous day" , "Brink" , "Girl" , "Day before; girl's name" .)