|What is the difference between a congress and a conference?|
The IAPCO Meeting Industry Terminology publication, which is used a "dictionary for the congress industry", uses the following definitions:
Congress: Regular coming together on a representational basis of several hundreds - or even thousands - of individuals belonging to a single professional, cultural, religious or other group. A congress is often convened to discuss a particular subject. Contributions to the presentation and discussion of the subject matter come only from members of the organising body. Frequency: usually established in advance and can be either multiannual or annual. Most international or world congresses are of the former type while national congresses are more frequently held annually. A congress will often last several days and have several simultaneous sessions.
Conference: Participatory meeting designed for discussion, fact-finding, problem solving and consultation. As compared with a congress, a conference is normally smaller in scale and more select in character - features which tend to facilitate the exchange of information. The term "conference" carries no special connotation as to frequency. Though not inherently limited in time, conferences are usually of limited duration with specific objectives.
You can also find a definition on MICE in the following FAQ: