salutatory oration vs oratory

salutatory oration and oratory both are nouns.

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

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

salutatory oration: an opening or welcoming statement (especially one delivered at graduation exercises)
oratory: addressing an audience formally (usually a long and rhetorical address and often pompous)

salutatory oration (noun)	oratory (noun)
an opening or welcoming statement (especially one delivered at graduation exercises)	addressing an audience formally (usually a long and rhetorical address and often pompous)