Cutoff frequency.

The frequency at which the gain of a filter is at an edge of a band, usually taken to be when gain is 0.5, or -3.01dB; the frequency at which the output of a filter is half the power of the input; See Also: band-pass filter, high-pass filter, low-pass filter; Symbols: omega sub c; Typical Units: rad/s,Hz; Dimensions: 1/Time;