1. a material or device that prevents or reduces the passage of heat, electricity, or sound

Examples

• The ceramic insulator prevented the electrical current from reaching the metal pole.
• Foam insulation acts as an insulator to keep the house warm in winter.
• Glass is a good electrical insulator.
• The workers wore rubber gloves as insulators against electric shock.
• Double-paned windows use air as an insulator between the glass layers.
• The power lines were attached to ceramic insulators on the utility poles.