Learner's definition of CONVENTION
1 [count] : a large meeting of people who come to a place for usually several days to talk about their shared work or other interests or to make decisions as a group
We go to the weeklong annual teachers' convention every summer.
He bought some new books at the science fiction convention.
a constitutional convention [=a meeting in which political leaders create a constitution]
The Democratic National Convention will meet next week to announce their party's candidate for president.
The conference was held at the new convention center. [=a building or set of buildings designed to hold many people and meetings]
2 : a custom or a way of acting or doing things that is widely accepted and followed
It's important to follow the conventions of punctuation in a paper for school.
They say school is just as important for teaching children social codes and conventions as for teaching math.
Many sports shows have recently adopted the conventions of the talk show.
a poet who rebels against literary convention
The award that by convention should have gone to the student with the highest grade went instead to the teacher's favorite.
a director who has always defied convention [=done unexpected or unusual things] in his movies
As a matter of convention, the oldest members speak first.
3 [count] : a traditional or common style often used in literature, theater, or art to create a particular effect 4 [count], formal : a formal agreement between two groups (such as countries or political organizations)