convention
n. C / Un. a traditional way of doing something that most people in a group follow. It can also mean a large formal meeting for people who share the same job or interest.
n. a widely observed custom or established rule of social behaviour; alternatively, a formal assembly of delegates or members for a common purpose.
It is a social convention to shake hands when you meet someone.
The annual medical convention attracts thousands of doctors who want to learn about the latest research.
The artist chose to defy every established convention of portraiture, using abstract shapes and neon colours instead of realistic features to represent his subjects.
Recorded since about 1440, borrowed from Middle French convention, from Latin conventiō (“meeting, assembling; agreement, convention”), from conveniō (“come, gather or meet together, assemble”), from con- (“with, together”) + veniō (“come”). Equivalent to convene + -tion.
Countable when referring to a specific meeting or a particular rule; uncountable when referring to traditional behaviour in general.