The difference between Discourse and Ratiocination

When used as nouns, discourse means verbal exchange, conversation, whereas ratiocination means reasoning, conscious deliberate inference.

Discourse is also verb with the meaning: to engage in discussion or conversation.

check bellow for the other definitions of Discourse and Ratiocination

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).

Ratiocination as a noun:

Reasoning, conscious deliberate inference; the activity or process of reasoning.
Ratiocination as a noun:

Thought or reasoning that is exact, valid and rational.
Ratiocination as a noun:

A proposition arrived at by such thought.