Nut vessel? (3)
I believe the answer is:
tun
'vessel?' is the definition.
(type of vessel for beer)
'nut' is the wordplay.
'nut' anagrams to 'TUN'.
But, I am not clear how the anagram is indicated.
Can you help me to learn more?
(Other definitions for tun that I've seen before include "vessel" , "Nut found in large cask" , "'Large cask, for beer perhaps (3)'" , "Cask, vat" , "Large cask (holding 252 gallons)" .)