Meaning

noun a farewell oration (especially one delivered during graduation exercises by an outstanding member of a graduating class)

adjective of or relating to an occasion or expression of farewell

adjective of a speech expressing leave-taking

originFrom Latin valedictum + English -ory (suffix forming nouns meaning ‘that which pertains to’, or adjectives meaning ‘of or pertaining to’). Valedictum is the accusative supine of valedīcō (“to bid farewell; to give a valediction”), from valē (“farewell, goodbye”) (the imperative of valeō (“to be healthy or well; to be strong; to have influence or power”), ultimately from Proto-Indo-European…

Etymology from Wiktionary, CC BY-SA 3.0