Affectionate appellation (3,4)
I believe the answer is:
pet name
'affectionate appellation' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for pet name that I've seen before include "what one gets from cat-callers?" , "Familiar appellation" , "Term of endearment" , "Fond appellation" .)