Gathering in central section in empty doorway (6,5)
I believe the answer is:
dinner party
'gathering' is the definition.
(dinner party is a kind of gathering)
'central section in empty doorway' is the wordplay.
'central' becomes 'inner' (similar in meaning).
'section' becomes 'part' (synonyms).
'in' is an insertion indicator.
'empty doorway' becomes 'dy' (I am not sure about this - if you are sure you should believe this answer much more).
'inner'+'part'='innerpart'
'innerpart' inserted inside 'dy' is 'DINNER PARTY'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for dinner party that I've seen before include "Social gathering over a meal" , "Sociable gathering for meal" , "social function" .)