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 material can endure before it becomes conductive, leading to a failure in insulation. This property is crucial for materials used in electrical applications, such as insulators and capacitors. The dielectric strength is typically expressed in volts per unit thickness, such as volts per millimeter. Higher dielectric strength indicates better insulating properties, making materials like ceramics and plastics ideal for protecting electrical components from short circuits and other failures.