Which term refers to the percentage of variation allowed from a resistor's nominal value?

The term that refers to the percentage of variation allowed from a resistor's nominal value is resistor tolerance. Tolerance is a critical specification in electronics, indicating how much a resistor's actual resistance can deviate from its stated value. For example, a resistor with a nominal value of 1,000 ohms and a tolerance of ±5% could vary between 950 ohms and 1,050 ohms. Understanding resistance tolerance is essential for designing and troubleshooting circuits, as it affects how components will perform under different conditions.

Other options in the question refer to different concepts. Resistance rating typically describes the nominal value of a resistor without addressing its potential variation. Voltage drop relates to the reduction in voltage across a component in a circuit and is not directly connected to how much the actual resistance can differ from the nominal. Current rating denotes the maximum current a component can handle safely but does not pertain to resistance variation. Hence, resistor tolerance is the correct term that accurately describes the concept of permissible variation in resistance values.