The reciprocal of impedance is called :

Admittance is the reciprocal of impedance

The reciprocal of impedance is called admittance. Impedance, in electrical engineering, is a measure of how much a circuit resists the flow of alternating current (AC). It combines both resistance and reactance (which includes inductance and capacitance) into a single complex quantity. Impedance is typically represented by the symbol $Z$, and it is measured in ohms (Ω).

Admittance, on the other hand, is the measure of how easily a circuit allows the flow of alternating current. It is essentially the "ease" with which current flows in response to an applied voltage. Mathematically, admittance is the reciprocal of impedance and is denoted by the symbol $Y$. It is expressed in units called siemens (S).