valedictory

Of or pertaining to a valediction (“an act of parting company; a speech made when parting company”); designed for or suitable to an occasion of bidding farewell or parting company.

(US, Canada) Of or pertaining to a valedictorian (“the individual in a graduating class who delivers the farewell address, often the person who graduates with the highest grades”).

An address given on an occasion of bidding farewell or parting company.

(US, Canada) A speech given by a valedictorian at a commencement or graduation ceremony.