The Z name refers to the characteristic impedance of the oscilloscope and cable.
It had a characteristic impedance of 50 Ω, and was adopted for use in the emerging broadcast industry.
The resistors are chosen to match the characteristic impedance of the sense lines.
The cable has a characteristic impedance of either 50 or 52 Ω.
The product of and from the above formula is known as the characteristic acoustic impedance.
Each type of transmission line has a specific characteristic impedance.
Correct operation requires matched characteristic impedance at all four ports.
The cable used must have the same characteristic impedance as the component.
It also results in a purely real (resistive) characteristic impedance.
This results in a step change in the characteristic impedance of the waveguide.