Overshoot
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In telecommunication, the term overshoot has the following meanings:
1. In the transition of any parameter from one value to another, the transitory value of the parameter that exceeds the final value.
Note: Overshoot occurs when the transition is from a lower value to a higher value. When the transition is from a higher value to a lower value, and the parameter takes a transitory value that is lower than the final value, the phenomenon is called "undershoot." See Gibbs phenomenon.
2. The increased amplitude of a portion of a nonsinusoidal waveform, i.e. signal, at the output of a nonlinear circuit, e.g. a realizable amplifier, caused by the characteristics of the circuit.
Note 1: Overshoot causes distortion of the signal.
Note 2: Overshoot may result from circuit design parameters that are intended to decrease the response time of the circuit.
Note 3: The amount of overshoot in a given circuit is designed to minimize response time while maintaining distortion of the signal within acceptable limits. The absence or presence of overshoot, and if present, its magnitude, is a function of a circuit design parameter called "damping." See illustration under waveform.
3. The result of an unusual atmospheric, e.g., ionospheric, condition that causes microwave signals to be received where they are not intended.
Source: from Federal Standard 1037C and from MIL-STD-188
In control theory the percentage overshoot is the maximum value minus the step value divided by the step value. In the case of the unit step, the overshoot is just the maximum value of the step response minus one.
In aviation, an overshoot is an aborted landing. See: go around.