In telecommunication, the term delay has the following meanings:

1. The amount of time by which an event is retarded.

2. The time between the instant at which a given event occurs and the instant at which a related aspect of that event occurs.

Note 1: The events, relationships, and aspects of the entity being delayed must be precisely specified.

Note 2: Total delay may be demonstrated by the impulse response of a device or system.

Note 3: In analog systems, total delay is described in terms of the transfer functions in the frequency domain. Synonym delay time.

3 . In radar, the electronic delay of the start of the time base used to select a particular segment of the total.

Source: from Federal Standard 1037C and from MIL-STD-188