, attack time
is the time
between (a) the instant that a signal
at the input
of a device or circuit
exceeds the activation threshold
of the device or circuit and (b) the instant that the device or circuit reacts in a specified manner, or to a specified degree, to the input.
Note: Attack time occurs in devices such as clippers, peak limiters, compressors, and voxes.
Source: from Federal Standard 1037C
See also: Fall time.