耐寒 (nàihán) literally combines 耐 (nài), meaning 'to endure' or 'to withstand', and 寒 (hán), meaning 'cold' or 'coldness'. Together, they form an adjective meaning 'cold-resistant'—describing living things (especially animals and plants) that can survive low temperatures without harm. It emphasizes biological resilience rather than mechanical or material insulation.

This term is commonly used in biology, agriculture, horticulture, and veterinary contexts. For example, breeders may select for耐寒 traits in livestock, and gardeners choose耐寒 plant varieties for northern climates. It’s rarely used for non-living objects; for those, terms like 'cold-proof' or 'frost-resistant' (防冻 fángdòng) are more appropriate. The word often appears in compound phrases such as 耐寒性 (nàihánxìng, 'cold tolerance') or 耐寒品种 (nàihán pǐnzhǒng, 'cold-tolerant variety').