From Longman Dictionary of Contemporary Englishinsulatorin‧su‧la‧tor /ˈɪnsjəleɪtə $ ˈɪnsəleɪtər/ noun [countable] TPEa material or object which does not allow electricity, heat, or sound to pass through it OPP conductor Wood is an excellent insulator.
Examples from the Corpus
insulator• A couple of minutes must pass before the accumulator vanes behind the hood re-energized the conductors and insulators.• Non-metals tend to be insulators although, as we have seen, graphite is a conductor of electricity.• Materials that do not conduct heat well are called insulators. 61.• Still embedded high on a rock is a tangle of telephone wires and a ceramic insulator.• Their advantages are: The frame members are good insulators, so condensation is not a problem.• The sand serves as natural insulator, and some of the more massive pieces take long to cool.• The power station was in poor repair, and Smith set about installing new insulators and restoring good practice.• It could serve as a heat conductor or insulator, depending on how it was used. 