Sets jams? (5)
I believe the answer is:
packs
I believe this is a double definition.
'sets' is the first definition.
(pack is a kind of set)
'jams?' is the second definition.
('pack' can be a synonym of 'jam')
(Other definitions for packs that I've seen before include "Prepares gifts, say" , "prepares to leave" , "Crowds" , "Cartons" , "Given cards" .)