wintering; passing the winter
Refers to spending the winter in a particular place or condition, often used for plants, animals, or people staying somewhere through the cold season.
ツバメは暖かい国で冬越しをする。
Swallows winter in warm countries.
It's better to overwinter this plant indoors.
Compound of 冬 (ふゆ, 'winter') and 越し (ごし, the continuative form of 越す, 'to pass over'). Literally 'passing over winter'.