The height of joy, welcoming European victory? (9)
I believe the answer is:
elevation
'the height' is the definition.
(thesaurus)
'joy welcoming european victory?' is the wordplay.
'joy' becomes 'elation' (elation is a kind of joy**).
'welcoming' means one lot of letters goes inside another (in sense of 'inviting in').
'european' becomes 'e' (abbreviation e.g. EU).
'victory?' becomes 'v'.
'e'+'v'='ev'
'elation' enclosing 'ev' is 'ELEVATION'.
'of' is the link.
(Other definitions for elevation that I've seen before include "scale drawing" , "Height - a live note (anag)" , "high ground" , "plan" , "Drawing of the external face of a building" .)