This is an important term. Capacitive Reactance is the opposition offered by a capacitor to the alternating current flow, or simply AC current. A capacitor resists the change in the flow of current and hence it shows some opposition which can be termed as reactance, as the frequency of the input current should also be considered along with the resistance it offers.

Symbol: X_C

In a purely capacitive circuit, the current I_C leads the applied voltage by 90°