Wiktionary
susceptance
n. (context physics English) the imaginary component of the admittance of an alternating current circuit
Wikipedia
Susceptance
In electrical engineering, susceptance (B) is the imaginary part of admittance. The inverse of admittance is impedance, and the real part of admittance is conductance. In SI units, susceptance is measured in siemens. Oliver Heaviside first defined this property, which he called permittance, in June 1887.