Lucerne redeveloped to house very big arena (9)
I believe the answer is:
enclosure
'arena' is the definition.
(thesaurus)
'lucerne redeveloped to house very big' is the wordplay.
'redeveloped' is an anagram indicator.
'to house' means one lot of letters goes inside another.
'very big' becomes 'os' (abbreviation for outsize).
'lucerne' is an anagram of 'enclure'.
'enclure' enclosing 'os' is 'ENCLOSURE'.
(Other definitions for enclosure that I've seen before include "Sealed-off area" , "What's in the envelope" , "compound" , "pound" , "Document included with a letter" .)