Relationship formed by medium putting time in for daughter (5)
I believe the answer is:
ratio
'relationship' is the definition.
(relationship between two numbers)
'by medium putting time in for daughter' is the wordplay.
I cannot really see how this works, but
'by' could be 'at' and 'at' is found in the answer.
The remaining letters 'rio' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'formed' is the link.
(Other definitions for ratio that I've seen before include "Comparative measure" , "Proporation, quantitative relation" , "Expression of relationship" , "E.g. sin i" , "Relationship between two amounts" .)