Dielectric strength is a measure of a material's ability to withstand electric fields without breaking down. It is defined as the maximum electric field that a dielectric material can endure before it becomes conductive, leading to a failure in insulation. This property is crucial in electrical engineering, as it helps determine the suitability of materials for insulating components like wires and capacitors. The dielectric strength is typically expressed in volts per unit thickness, such as volts per millimeter. Materials with high dielectric strength, like ceramics and glass, are often used in applications where high voltage is present, ensuring safety and reliability in electrical systems.