conference vs discussion

conference and discussion both are nouns.

Word	Noun	Adjective	Verb	Adverb
conference	Yes	No	No	No
discussion	Yes	No	No	No

As nouns, discussion is a hypernym of conference; that is, discussion is a word with a broader meaning than conference:

conference: a discussion among participants who have an agreed (serious) topic
discussion: an exchange of views on some topic

Other hypernyms of conference include give-and-take, word.

conference (noun)	discussion (noun)
a discussion among participants who have an agreed (serious) topic	an exchange of views on some topic
a prearranged meeting for consultation or exchange of information or discussion (especially one with a formal agenda)	an extended communication (often interactive) dealing with some particular topic
an association of sports teams that organizes matches for its members