colloquium
Concise Oxford English Dictionary © 2008 Oxford University Press:
colloquium /kəˈləʊkwɪəm/
▶noun (pl. colloquiums or colloquia /-kwɪə/) an academic conference or seminar.
– origin C16 (denoting a conversation): from L., from colloqui ‘to converse’.
'colloquium' also found in these Oxford entries:

