The measure of a material's resistance to the flow of electric current is electrical resistance.
Resistance describes how strongly a material or component opposes the movement of electric charge. It is measured in ohms, represented by the Greek letter Ω. In a simple circuit, a resistor converts electrical energy into thermal energy as current passes through it.
Ohm's law expresses the relationship as V = IR: voltage equals current multiplied by resistance. For a given voltage, increasing resistance reduces current. Resistance depends on a material's resistivity, its length, and its cross-sectional area; a longer, thinner wire generally has more resistance than a shorter, thicker wire of the same material.
Resistance is not the same as conductance, which measures ease of current flow and is its reciprocal. Capacitance concerns stored electric charge, while impedance is the broader opposition to alternating current and can include resistance plus reactance.