valediction vs oratory

valediction and oratory both are nouns.

Word	Noun	Adjective	Verb	Adverb
valediction	Yes	No	No	No
oratory	Yes	No	No	No

As nouns, oratory is a hypernym of valediction; that is, oratory is a word with a broader meaning than valediction:

valediction: a farewell oration (especially one delivered during graduation exercises by an outstanding member of a graduating class)
oratory: addressing an audience formally (usually a long and rhetorical address and often pompous)

valediction (noun)	oratory (noun)
the act of saying farewell	addressing an audience formally (usually a long and rhetorical address and often pompous)
a farewell oration (especially one delivered during graduation exercises by an outstanding member of a graduating class)