What is the function of hysteresis in a comparator?

Hysteresis in a comparator circuit establishes two separate threshold voltages: one for a rising input signal and a slightly lower one for a falling input signal. This separation creates a dead band or margin between the switching points. The primary function of this dead band is to prevent input noise from causing the comparator's output to rapidly bounce back and forth (oscillate) when the signal is hovering right at the threshold. Without hysteresis, even minor electrical noise could trigger unstable output states. Distractors claiming it increases sensitivity are incorrect; hysteresis intentionally reduces sensitivity to minor voltage fluctuations near the threshold.