1a way in which something is usually done:to attract the best patrons the movie houses had to ape the conventions and the standards of theatres
[mass noun] behaviour that is considered acceptable or polite to most members of a society:he was an upholder of convention and correct form [count noun]:the law is felt to express social conventions
2an agreement between states covering particular matters, especially one less formal than a treaty:the convention, signed by the six states bordering on the Black Sea, aims to prevent further pollution
3a large meeting or conference, especially of members of a political party or a particular profession or group:the party held its biennial convention
North American an assembly of the delegates of a political party to select candidates for office.
a body set up by agreement to deal with a particular issue:the convention is a UN body responsible for the regulation of sea dumping
historical a meeting of Parliament without a summons from the sovereign.
4 Bridge a bid or system of bidding by which the bidder tries to convey specific information about the hand to their partner, as opposed to seeking to win the auction.