1. materials that do not allow electricity, heat, or sound to pass through easily
Usage: physics; engineering
2. devices used to prevent the flow of electric current between conductors
Usage: electrical engineering

Examples

• Rubber and plastic are common electrical insulators.
• The power lines were supported by ceramic insulators on the poles.
• Glass insulators were widely used on telegraph lines in the past.
• Good thermal insulators help keep buildings warm in winter.
• The electrician replaced the damaged insulators on the transmission tower.
• Wood and cork are natural insulators that resist heat transfer.
• The laboratory used special insulators to prevent electrical interference.