$\textit{Conductance}$, for a resistive two-terminal element or two-terminal circuit with terminals A and B, quotient of the electric current i in the element or circuit by the voltage $u_{AB}$ between the terminals: $G = \frac{1}{R}$, where the electric current is taken as positive if its direction is from A to B and negative in the opposite case. The conductance of an element or circuit is the inverse of its resistance.
Applicable units are those of quantitykind:Conductance
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http://www.electropedia.org/iev/iev.nsf/display?openform&ievref=131-12-06
$G = Re\underline{Y}$, where $\underline{Y}$ is admittance.
Alternatively:
$G = \frac{1}{R}$, where $R$ is resistance.