Symposium or Kegger

I have been attending a conference this weekend. These are usually a cause of both boredom and great amusement. It has generally been an informative weekend although I am quite sleep-deprived and over-caffeinated. (Even more than normal due to daylight saving time.)

A colleague leaned over to me during a presentation last night and asked a question that I couldn't answer. "What does plenary mean?" I understand the word in context, but the best definition I could provide for a plenary speaker was "super special invited speaker." Asking around at the social hour later didn't provide any better definition. But it garnered the suggestion to also look up the word symposium in the dictionary. So today I pulled up the Oxford English Dictionary, and I now wish to share the results with you for your enlightenment and amusement.Plenary (adj)
1. Full, complete, or perfect; not deficient in any element or respect; absolute.
2. Of an assembly, conference, etc.: having all members in attendance; fully constituted, fully assembled; esp. attended by all participants, who otherwise meet in smaller groups.

Symposium (noun)
1. A drinking-party; a convivial meeting for drinking, conversation, and intellectual entertainment: properly among the ancient Greeks, hence generally.
2. A meeting or conference for discussion of some subject; hence, a collection of opinions delivered, or a series of articles contributed, by a number of persons on some special topic.