Jerry's ice cream partner (3)
I believe the answer is:
ben
'jerry's ice cream partner' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ben that I've seen before include "A Scottish mountain like Nevis" , "Second part of 11" , "Battle" , "inner room in Oban, say" , "He's big in London" .)