valediction vs valedictory address

valediction and valedictory address both are nouns.

Word	Noun	Adjective	Verb	Adverb
valediction	Yes	No	No	No
valedictory address	Yes	No	No	No

As nouns, valediction and valedictory address are synonyms defined as:

valediction and valedictory address: a farewell oration (especially one delivered during graduation exercises by an outstanding member of a graduating class)

Other synonyms of valediction include valedictory, valedictory oration.

valediction (noun)	valedictory address (noun)
the act of saying farewell	a farewell oration (especially one delivered during graduation exercises by an outstanding member of a graduating class)
a farewell oration (especially one delivered during graduation exercises by an outstanding member of a graduating class)