1. a usual or accepted way of behaving
to flout convention, to do something unconventional
‘Convention’ refers to a way of conducting oneself that is considered to be correct or polite by society at large, or a traditional method of doing something. It particularly applies to social situations rather than behaviour in the home. To break convention may not be against the law, but it will often result in a negative reaction from people around you. The opposite is ‘unconventional’.
Convention dictates that I will have to wear a suit to this event, but I’d be much more comfortable in jeans and a jumper.
The artist wasn’t interested in taking a conventional approach to her work. She wanted to create something daring and different.