Nut container? (3)
I believe the answer is:
tun
'container?' is the definition.
(type of cask)
'nut' is the wordplay.
'nut' can be anagrammed to 'TUN'.
But, I am unsure how this is indicated.
Can you help me to learn more?
(Other definitions for tun that I've seen before include "butt" , "Large cask for wine or beer" , "'Large cask, for beer perhaps (3)'" , "Nut found in large cask" , "Cask, vat" .)