The ceremony is correct, we hear (4)
I believe the answer is:
rite
'the ceremony' is the definition.
(rite is a kind of ceremony)
'correct we hear' is the wordplay.
'correct' becomes 'right' (right can mean correct).
'we hear' shows a homophone (sound like).
'right' is a homophone of 'RITE'.
'is' is the link.
(Other definitions for rite that I've seen before include "Tire of ceremony" , "(Words used in) ceremonial" , "Ceremony, liturgy" , "Ceremonial act" , "Formal procedure" .)