valedictory oration vs oratory

valedictory oration and oratory both are nouns.

Word	Noun	Adjective	Verb	Adverb
valedictory oration	Yes	No	No	No
oratory	Yes	No	No	No

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

valedictory oration: 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)

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