impedance definition
The definition of an impedance is any obstruction, or the measure of the opposition of an electric current to the energy flow when voltage is applied. 1  An example of impedance is when a school marching band cannot participate in a parade because they can't affort the cost of gas for the bus. An example of impedance is a line of resistance within an electrical current. the total opposition offered by an electric circuit to the flow of an alternating current of a single frequency: it is a combination of resistance and reactance and is measured in ohms: the reciprocal of admittance: symbol, Z.