'Reactance' definitions:

Definition of 'reactance'

noun

Opposition to the flow of electric current resulting from inductance and capacitance (rather than resistance)

From: GCIDE

Reactance \Re*act"ance\ (r[-e]*[a^]k"tans), n. [React + -ance.] (Elec.) The influence of a coil of wire upon an alternating current passing through it, tending to choke or diminish the current, or the similar influence of a condenser; inductive resistance. Reactance is measured in ohms. The reactance of a circuit is equal to the component of the impressed electro-motive force at right angles to the current divided by the current, that is, the component of the impedance due to the self-inductance or capacity of the circuit. [Webster 1913 Suppl.]