What is the term for the opposition to AC current flow offered by a capacitor?

The correct term for the opposition to AC current flow offered by a capacitor is capacitive reactance. This specific type of reactance arises because capacitors store and release energy in an electric field, causing a phase difference between the voltage across the capacitor and the current flowing through it.

In an AC circuit, as the frequency of the current increases, the capacitive reactance decreases, allowing more AC current to flow. This behavior differs from resistance, which is a constant opposition to current regardless of frequency. Inductive reactance, on the other hand, is associated with inductors, which oppose the change of current with a phase shift in the opposite direction. Impedance is a broader term that encompasses both resistance and reactance in an AC circuit but does not specify the capacitive aspect. Thus, the term capacitive reactance precisely describes the opposition to AC current presented by a capacitor.