A piece of stone, wood, or metal that lies under an outside door.

In a modulation system, the smallest value of carrier- to-noise ratio at the input to the demodulator for all values above which a small percentage change in the input carrier-to-noise ratio produces a substantially equal or smaller percentage change in the output signal-to-noise ratio.

The least value of a current, voltage, or other quantity that produces the minimum detectable response in an instrument or system.

See <<riegel>>

A logic operator such that, if P, Q, R, S, ... are statements, then the threshold will be true if at least N statements are true, false otherwise.

The minimum level of some input quantity needed for some process to take place, such as a threshold energy for a reaction, or the minimum level of pumping at which a laser can go into self-excited oscillation.

The minimum level of a stimulus that will evoke a response in an irritable tissue.