Journey’s end in entering key European terminus perhaps (11)
I believe the answer is:
destination
'journey's end' is the definition.
(I've seen this before)
'in entering key european terminus perhaps' is the wordplay.
'entering' means one lot of letters goes inside another.
'key european' becomes 'de' (I can't explain this - if you can you should give a lot more credence to this answer).
'terminus perhaps' becomes 'station' (terminus is a kind of station).
'de'+'station'='destation'
'in' put within 'destation' is 'DESTINATION'.
Can you help me to learn more?
(Other definitions for destination that I've seen before include "Journey's end" , "terminal" , "Place to which one is travelling" , "Where one is going" , "Final goal" .)