Stein relative (7)
I believe the answer is:
tankard
'stein relative' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tankard that I've seen before include "One-handled beer mug" , "Beer-mug" , "Mug-like drinking vessel" , "Drinking vessel with a handle" , "Tall beer mug" .)