Daughter nowadays is relative (3)
I believe the answer is:
dad
'relative' is the definition.
(dad is a kind of relative)
'daughter nowadays' is the wordplay.
'daughter' becomes 'd'.
'nowadays' becomes 'ad'.
'd'+'ad'='DAD'
'is' is the link.
(Other definitions for dad that I've seen before include "Mum's mate" , "Pop, pater" , "Relation" , "Father, in short" , "Popular and informal father" .)