insulator
substance that does not transmit certain forms of energy, such as heat (thermal insulator), sound (acoustic insulator) or electricity (electrical insulator)
en-US/ˈɪnsəˌleɪdɚ/
en-GB/ˈɪnsuːˌleɪtə/
substance that does not transmit certain forms of energy, such as heat (thermal insulator), sound (acoustic insulator) or electricity (electrical insulator)