nuclear winter
noun [ C usually singular ] physics specialized uk/ˌnjuː.klɪə ˈwɪn.tər/ us/ˌnuː.kliː.ɚ ˈwɪn.t̬ɚ/
核冬季（科学家假设的在巨大核爆炸后一段寒冷黑暗、生物灭绝的时期）
a period that scientists believe would follow a large nuclear explosion, when there would be very little light or heat and nothing would grow in the world