The difference between Discourse and Oration

When used as nouns, discourse means verbal exchange, conversation, whereas oration means a formal, often ceremonial speech.

When used as verbs, discourse means to engage in discussion or conversation, whereas oration means to deliver an oration.

check bellow for the other definitions of Discourse and Oration

Discourse as a noun (uncountable, archaic):

Verbal exchange, conversation.
Discourse as a noun (uncountable):

Expression in words, either speech or writing.
Discourse as a noun (countable):

A formal lengthy exposition of some subject, either spoken or written.

Examples:

"The preacher gave us a long discourse on duty."
Discourse as a noun (countable):

Any rational expression, reason.
Discourse as a noun (social sciences, countable):

An institutionalized way of thinking, a social boundary defining what can be said about a specific topic (after Michel Foucault).
Discourse as a noun (obsolete):

Dealing; transaction.

Discourse as a verb (intransitive):

To engage in discussion or conversation; to converse.
Discourse as a verb (intransitive):

To write or speak formally and at length.
Discourse as a verb (obsolete, transitive):

To debate.
Discourse as a verb:

To exercise reason; to employ the mind in judging and inferring; to reason.

Examples:

"rfquotek Dryden"
Discourse as a verb (obsolete, transitive):

To produce or emit (musical sounds).

Oration as a noun:

A formal, often ceremonial speech.

Examples:

"a funeral oration; an impassioned oration; to make / deliver / pronounce an oration"
Oration as a noun (jocular):

A lengthy speech or argument in a private setting.
Oration as a noun (Catholicism):

A specific form of short, solemn prayer said by the president of the liturgical celebration on behalf of the people.