Formal speech or lecture (7)
I believe the answer is:
address
I believe this is a double definition.
'formal speech' is the first definition.
(I've seen this in another clue)
'lecture' is the second definition.
(address a speech to an audience)
(Other definitions for address that I've seen before include "Speak to - direct" , "Deliver a speech" , "directions in window" , "Speak formally to an audience" , "Give a talk to" .)