What does acoustic reactance mean?

Here's a list of possible definitions for the term acoustic reactance:

acoustic resistance, acoustic impedance, acoustic reactance(noun)
opposition to the flow of sound through a surface; acoustic resistance is the real component of acoustic impedance and acoustic reactance is the imaginary component

acoustic reactance
Acoustic impedance and specific acoustic impedance are measures of the opposition that a system presents to the acoustic flow resulting from an acoustic pressure applied to the system. The SI unit of acoustic impedance is the pascal-second per cubic metre (Pa·s/m3), or in the MKS system the rayl per square metre (rayl/m2), while that of specific acoustic impedance is the pascal-second per metre (Pa·s/m), or in the MKS system the rayl. There is a close analogy with electrical impedance, which measures the opposition that a system presents to the electric current resulting from a voltage applied to the system.

acoustic reactance
Acoustic reactance is a property of an acoustic system that measures the opposition to the change of acoustic flow rate through the system due to its inertia or elasticity. It is a kind of acoustic resistance that reacts to changes in sound pressure and air flow, and can affect the transmission and resonance of sound waves.

Chaldean Numerology
The numerical value of acoustic reactance in Chaldean Numerology is: 3
Pythagorean Numerology
The numerical value of acoustic reactance in Pythagorean Numerology is: 8