Extracurricular means happening at school but outside the lessons. Extracurricular activities, an extracurricular club, extracurricular sport.
Universities and employers weigh these activities heavily, which turns something meant to be voluntary into another thing to be judged on. The extra- means outside rather than additional, so extracurricular is literally beyond the curriculum. Note the joking use for an affair — extracurricular activities — which relies on exactly that sense of outside the official.
1adjectiveextracurricularHappening at school but outside the lessons.
“The school offers extracurricular activities such as chess club, drama and football.”
extracurricular is a quality of being outside lessons.
EXTRA-curricular → EXTRA, on top of the lessons
The last lesson ends and the school does not empty. The band stays in one room, the chess club takes another, the team goes out to the field: all of it extra, on top of the day.
hooks ontoextra
From extra- + curricular.
Etymology from Wiktionary, CC BY-SA