Open English Wordnet
Nouns
(n)valediction, valedictory address, valedictory oration, valedictorya farewell oration (especially one delivered during graduation exercises by an outstanding member of a graduating class)
Adjectives
(a)valedictoryof or relating to an occasion or expression of farewell“a valedictory address”, “valedictory praise for his uniformly manly course”, “a suitable valedictory gesture”