Advent calendar
noun [ C ] uk/ˈæd.vent ˌkæl.ən.dər/ us/ˈæd.vent ˌkæl.ən.dɚ/
基督降临历（挂在墙上的装饰卡，上有小门，孩子们在12月1日至圣诞节前每天打开一扇小门就可看到里面的图画）
a decorative piece of card, often hung on the wall, that has a small opening with a door for each of the days of the month before Christmas. Children open one of these doors each day, finding a picture under it.