What is "monostable"

a. (context electronics English) Having more than one state, only one of which is stable.

A monostable multivibrator is an electronic circuit that generates an output pulse. When triggered, a pulse of pre-defined duration is produced. The circuit then returns to its quiescent state and produces no more output until triggered again.

Monostables may be considered as a biased form of multivibrator where it is stable in one state until triggered, then unstable and will return of its own accord.

If repeated application of the input pulse maintains the circuit in the unstable state, it is called a retriggerable monostable. If further trigger pulses do not affect the period, the circuit is a non-retriggerable monostable.