winter solstice
noun
1- the solstice at midwinter, at the time of the shortest day, about 22 December in the northern hemisphere and 21 June in the southern hemisphere冬至（一年中白昼最短的日子, 北半球约在12月22日, 南半球约在6月21日）。
1.1
- Astronomy the solstice in December【天文】冬至点。