formal
n. countablen. a very important dance or party at a school or university where people wear their best clothes. You usually go to this event at the end of the school year.
n. a social event or dance, typically held at the conclusion of an academic year, requiring evening dress or high-standard attire. Common in North American and Australian educational contexts.
She bought a long blue dress for the school formal.
The senior students spent months planning the winter formal, from the catering menu to the professional photography.
While the university formal is ostensibly a celebration of academic completion, it also serves as a significant rite of passage for students transitioning into professional life.
From Middle English formel, borrowed from Old French formel, from Latin fōrmālis, from fōrma (“form”); equivalent to form + -al.
See formo-.
Often used as a synonym for 'prom' in certain dialects, particularly in Australia and parts of Canada.