In which Nelson had this (7)
I believe the answer is:
victory
'in which nelson had this' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
This is all the clue.
Can you help me to learn more?
(Other definitions for victory that I've seen before include "Win" , "ship" , "Opposite of defeat" , "Successful ending to a struggle or contest" , "See 8" .)