耐热 (nàirè) is an adjective meaning 'heat-resistant' or 'able to withstand high temperatures.' It combines two characters: 耐 (nài), meaning 'to endure' or 'to withstand,' and 热 (rè), meaning 'heat' or 'high temperature.' Together, they describe a material, organism, or object’s capacity to tolerate heat without damage or functional loss. This term is commonly used in scientific, agricultural, and industrial contexts — for example, when describing plant varieties bred for hot climates or materials like ceramics and alloys used in engines or cookware.

While it can technically apply to animals or machines, its most frequent usage is in botany (e.g., drought- and heat-tolerant crop strains) and materials science. It functions attributively before nouns (e.g., 耐热玻璃 — heat-resistant glass) or predicatively with 是 or 很 (e.g., 这种塑料很耐热 — this plastic is highly heat-resistant). It is not used for temporary or subjective states, nor for people enduring discomfort (for which 忍耐 or 耐得住 is preferred).