the.com/advent calendar

means A calendar with small windows or compartments numbered for each day of December leading up to Christmas, opened one per day to reveal a treat, picture, or small gift.

from From Latin 'adventus,' meaning 'arrival' or 'coming' — the Christian season of Advent marks the weeks of anticipation before Christmas. The physical calendar itself is a 19th-century German tradition: devout families would mark the days, sometimes chalking lines on a door or lighting a candle, before printed calendars with doors to open emerged in the early 1900s. The chocolate-filled version came later, turning spiritual anticipation into a daily sugar ritual.