Matinee is improved by facilities (9)
I believe the answer is:
amenities
'facilities' is the definition.
(I have seen 'Useful facilities ' mean 'amenities' so perhaps 'facilities' could also mean 'amenities')
'matinee is improved' is the wordplay.
'improved' indicates an anagram.
'matinee'+'is'='matineeis'
'matineeis' is an anagram of 'AMENITIES'.
'by' is the link.
(Other definitions for amenities that I've seen before include "Equipment" , "useful services?" , "pleasing features" , "conveniences" , "Useful facilities" .)