the act of covering something to stop heat, sound, or electricity from escaping or entering, or the fact that something is covered in this way

The animal's thick fur provides very good insulation against the arctic cold. 动物的厚皮毛是防御极地寒冷的绝好材料。

material that is used to stop heat, sound, or electricity from escaping or entering

Glass fibre is often used as roof insulation. 玻璃纤维常用作屋顶的隔热材料。