A mug’s surname? (5)
I believe the answer is:
stein
This clue could be a double definition.
'a mug's' is the first definition.
(stein is a kind of mug)
'surname?' is the second definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
Can you help me to learn more?
(Other definitions for stein that I've seen before include "Gertrude ---; US writer" , "Gertrude __, avant-garde US author, d. 1946" , "German tankard" , "Inset into earthenware mug for beer" , "Large earthenware beer mug" .)