Attack time

In telecommunication, 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