\Re*act"ance\, 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.