Electrically a threshold usually means a measurement point above which a different action takes place than below that point.
For example I can use a difference amplifier with a zero reference point (threshold) to provide zero-crossing information from an AC voltage waveform. If that zero reference point is changed to 0.5 * Vpeak of a sine wave, then the difference amplifier will change state (+ vs -) at 30 and 120 degrees from a positive slope zero-crossing.
I can go to a trailer store and buy an AC voltmeter with a range of 96 to 134 V. I would describe this meter as having a threshold of 96 V on the minimum side,
You need to more completely describe your problem.
