Reactance may refer to:
Electrical reactance, the opposition to a change in voltage due to capacitance (capacitive reactance) or in current due to inductance (inductive reactance); the imaginary component of AC impedance Magnetic reactance, a similar effect in magnetism Reactance (psychology), an emotional reaction to pressure or persuasion that results in the strengthening or adoption of a contrary belief
See also Reactants, chemical reagents Reactivity (disambiguation)