Support opera's return (4)
I believe the answer is:
stem
'support' is the definition.
(I've seen this before)
'opera's return' is the wordplay.
'opera's' becomes 'met's' (Metropolitan Opera in New York).
'return' shows that the letters should be reversed in order.
'mets' backwards is 'STEM'.
(Other definitions for stem that I've seen before include "Peduncle" , "Main stalk of a plant" , "Central upright part of flower or drinking glass" , "Originate (from)" , "Basic skiing turn" .)