This is the 9614th most frequent Japanese word.
耐熱
Heat-resistant.
In this sentence, "耐熱性" (tainetsu-sei) refers to heat resistance as a property of the dish.
この皿は耐熱性があります。
This dish has heat resistance.
Here, "耐熱ガラス" (tainetsu-garasu) is used as a compound noun meaning "heat-resistant glass."
耐熱ガラスのコップを買いました。
I bought a heat-resistant glass cup.
In this example, "耐熱温度" (tainetsu-ondo) discusses the temperature up to which an object can resist heat.