Reference given by uncle? (8)
I believe the answer is:
relation
I believe this is a double definition.
'reference' is the first definition.
(eg 'in relation to' means 'in reference to')
'uncle?' is the second definition.
(uncle is a kind of relation)
'given by' acts as a link.
(Other definitions for relation that I've seen before include "Person related by blood or marriage" , "Story-telling - member of the family" , "Telling" , "Respect" , "Story; member of family" .)