Wire gauge refers to the measurement of the diameter of a wire, which is crucial in determining its electrical conductivity and current-carrying capacity. The gauge number is inversely related to the wire's diameter; a smaller gauge number indicates a thicker wire. For example, a 10-gauge wire is thicker than a 20-gauge wire. Different applications require specific wire gauges to ensure safety and efficiency. For instance, in household wiring, a 12-gauge wire is commonly used for lighting circuits, while a 14-gauge wire is often used for outlets. Choosing the correct wire gauge is essential to prevent overheating and electrical failures.