In which to find a drop of red in eatery? (6)
I believe the answer is:
carafe
'in which to' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'a drop of red in eatery?' is the wordplay.
'drop of' indicates taking the first letters.
'in' means one lot of letters goes inside another.
'eatery?' becomes 'cafe'.
The initial letter of 'red' is 'r'.
'a'+'r'='ar'
'ar' inserted inside 'cafe' is 'CARAFE'.
'find' is the link.
(Other definitions for carafe that I've seen before include "in which one has wine?" , "Wine is decanted into it" , "Open-topped glass flask" , "Decanter" , "Glass water jug" .)