Were in jug (4)
I believe the answer is:
ewer
'jug' is the definition.
(type of vessel)
'were' is the wordplay.
'were' can be anagrammed to 'EWER'.
But, I'm unsure how the anagram is indicated.
'in' is the link.
Can you help me to learn more?
(Other definitions for ewer that I've seen before include "29 [VESSEL]" , "Sort of jug" , "A wide-mouthed water-jug" , "Jar for water" , "Jug with wide spout" .)