Pop an article in the very centre of the middle! (3)
I believe the answer is:
dad
'pop' is the definition.
(both can mean one's father)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for dad that I've seen before include "Father, in short" , "Popular and informal father" , "Papa" , "Popular father - a palindrome" , "Relation" .)