Final answer:
The correct term for abnormal resistance interfering with signal flow is 'distortion'. Distortion alters the waveform of a signal due to factors like abnormal resistance, resistivity, and acoustic impedance.
Step-by-step explanation:
The term used to define abnormal resistance or impedance that interferes with the normal signal flow is distortion. In the context of waves and electrical circuits, distortion can arise when the electrical impedance causes changes in the signal as it propagates through a medium. This can affect both the amplitude and phase of the signal, leading to an altered waveform compared to the original.
According to the knowledge supplied, resistance is the property of materials to resist the passage of electric current, and in terms of signal propagation, an abnormal resistance can disrupt the normal flow and introduce distortion. Signals can be affected by various factors, such as resistance, resistivity, acoustic impedance, and the presence of impurities in materials, all of which can contribute to distortion.
Options such as reflectometry and reduction are not directly related to the concept of impedance that causes signal distortion, whereas discontinuity more commonly refers to a sudden break or change in the medium rather than abnormal impedance.