/ree ak"teuhns/ , n.
1. Elect. the opposition of inductance and capacitance to alternating current, expressed in ohms: equal to the product of the sine of the angular phase difference between current and voltage and the ratio of the effective voltage to the effective current. Symbol: X Cf. capacitive reactance, inductive reactance .
2. Acoustics. See acoustic reactance .
[ 1890-95; REACT + -ANCE ]