Hi I would say that the difference is in the role of the leaders at the event At a conference, one or more individuals will give formal speeches and then others at the event are invited to comment on what has been said. The leading speech is sometimes referred to as the keynote speech. The talk at the conference will usually be about what the main speakers have said At a seminar, there may be a group leader who will introduce the subject but they will not try to make their own thoughts the centre of the event.
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