Poppy's father? (5)

I believe the answer is:
daddy
This could be a double definition.
'poppy's' is the first definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'father?' is the second definition.
(daddy is a kind of father)
Can you help me to learn more?
(Other definitions for daddy that I've seen before include "Pa" , "Informal father" , "pop" , ">one of the Fathers" , "Papa" .)
