Which term is defined as the interval of time between the start of a response and its completion?

The term defined as the interval of time between the start of a response and its completion is correctly identified as Lag Time. Lag Time refers specifically to the delay that occurs between initiating an action or response and the moment when that action is actually completed. This term is often used in various fields to assess efficiency and timing, as it quantifies the time lost due to delays in response.

In contrast, Response Time typically describes the total time taken from the initiation of a request or input until the response is received, including Lag Time within it. Delay Time could be interpreted in a similar manner but is often used more generally to refer to any type of delay without specific reference to the completion of a task. Wait Time generally refers to the duration one might wait for something to happen without any proactive involvement in the process. These distinctions underscore why Lag Time is the precise term for this context.