What is the definition of an insulator?

An insulator is defined as a material that does not conduct heat well. This means that insulators resist the transfer of thermal energy, making them effective at maintaining temperature. Common examples of insulators include materials like rubber, glass, and certain plastics, which inhibit the flow of heat between two areas. This property is crucial in various applications, such as in building materials to keep homes warm in winter and cool in summer, or in electrical wiring to prevent unwanted heat transfer and protect against electrical hazards.

While some materials can conduct electricity well or reflect heat, those characteristics do not define an insulator. The main focus of the definition is specifically on the poor conduction of heat. Therefore, the correct understanding of an insulator centers on its function to limit heat transfer, as indicated in the answer provided.