Magazine articles held by William Morris (4)
I believe the answer is:
ammo
'magazine articles' is the definition.
(a magazine stores ammo or ammunition)
'held by william morris' is the wordplay.
'held by' indicates a hidden word.
'AMMO' is hidden within 'william morris'.
(Other definitions for ammo that I've seen before include "essential supplies for soldiers" , "Bullets, shells, etc. (abbr.)" , "explosives, perhaps" , "Slugs perhaps" , "Bullets (sl.)" .)