Occurring or existing outside the regular schedule or academic calendar.
From Latin 'extra' (outside) + 'calendarium' (account book, from 'calendae' meaning the first day of the month when accounts were due). Medieval calendars structured time officially; extracalendar originally meant outside recorded time.
Schools run on calendars with set schedules—extracalendar activities are the wild card programs that don't fit neatly into that official framework.
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