The day before a girl is found (3)
I believe the answer is:
eve
'the day before' is the definition.
(the eve of something is the night before)
I don't understand the remainder of the clue.
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" .)