1 a general agreement, esp. agreement on social behaviour etc. by implicit consent of the majority. b a custom or customary practice, esp. an artificial or formal one.
2 a a formal assembly or conference for a common purpose. b US an assembly of the delegates of a political party to select candidates for office. c hist. a meeting of Parliament without a summons from the sovereign.
3 a a formal agreement. b an agreement between States, esp. one less formal than a treaty.
4 Cards an accepted method of play (in leading, bidding, etc.) used to convey information to a partner.
5 the act of convening.
Etymology: ME f. OF f. L conventio -onis (as CONVENE)
Useful english dictionary. 2012.