Reactance defination

Can any one please explain me what is reactance??

the opposition to alternating current due to capacitance (capacitive reactance) or inductance (inductive reactance)

reactance is AC resistance that changes with frequency - can not be measured directly with a meter. It is caused by capacitors and inductors

could you be more specific? are you referring to electrical reactance or magnetic reactance or Chemical reactance or even psychological reactance?

as i may add to the contribution of other members:
In phasor analysis, reactance is used to compute amplitude and phase changes of sinusoidal alternating current going through the circuit element. It is denoted by the symbol *X*
Both reactance *X* and resistance *R* are required to calculate the impedance *Z* . In some circuits one of these may dominate, but an approximate knowledge of the minor component is useful to determine if it may be neglected.

Opposition to the flow of alternating current caused by the inductance and capacitance in a circuit rather than by resistance.