Discussion
Part of speech: noun
Definition: Conversation or debate concerning a particular topic. Text giving further detail on a subject.
Example sentence: If there are differences of views or divergence of ideas, they can be resolved through discussion and dialogue.
Discourse
Part of speech: verb
Definition: To engage in discussion or conversation; to converse.To write or speak formally and at length.To debate.
Part of speech: noun
Definition: Verbal exchange, conversation.Expression in words, either speech or writing.A formal lengthy exposition of some subject, either spoken or written.Any rational expression, reason.An institutionalized way of thinking, a social boundary defining what can be said about a specific topic (after Michel Foucault).
Example sentence: We must protect the very things that make America so special - most certainly including our civil liberties. But we cannot do so without strong national security and a thoughtful and informed discourse.