"Multilateral" generally refers to the relationship between many countries participating in the same international organization or activity. Bilateral talks refer to one-on-one negotiations between two countries on mutual relations (economic or security aspects).
Bilateral diplomatic negotiations refer to formal one-on-one negotiations between two countries on mutual relations (economy or security).
According to the Administrative Measures for Holding International Conferences in China issued by the Central Office and the State Council, international conferences refer to conferences, forums, seminars, reports and exchanges held in China (excluding Hong Kong, Macao and Taiwan) with participants from three or more countries and regions (excluding Hong Kong, Macao and Taiwan).
International conferences held by universities directly under the Ministry of Education shall be reported to the International Organization Department of the Department of International Cooperation and Exchange of the Ministry of Education for approval. The most fundamental principle of international conferences is equality between countries. Formal representatives enjoy equal representation and voting rights at the meeting.
Bilateral meetings refer to meetings, forums, seminars, reports and exchanges held in China (excluding Hong Kong, Macao and Taiwan) and attended by personnel from two countries and regions (excluding Hong Kong, Macao and Taiwan). Bilateral meetings are a special case of international meetings, and they also need to be reported to the International Organization Department of the International Cooperation and Exchange Department of the Ministry of Education for approval.