conference vs group meeting

conference and group meeting both are nouns.

Word	Noun	Adjective	Verb	Adverb
conference	Yes	No	No	No
group meeting	Yes	No	No	No

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

conference: a prearranged meeting for consultation or exchange of information or discussion (especially one with a formal agenda)
group meeting: a formally arranged gathering

Other hypernyms of conference include meeting.

conference (noun)	group meeting (noun)
a discussion among participants who have an agreed (serious) topic	a formally arranged gathering
a prearranged meeting for consultation or exchange of information or discussion (especially one with a formal agenda)
an association of sports teams that organizes matches for its members