Definition of Cycle Time
Cycle Time is the elapsed time between when a work item is started and when it is completed. Cycle Time is also referred to as a lagging indicator of flow.
Cycle Time is only available after an item is actually completed. For example, when it reaches the Done column on the Scrum board.
The Cycle Time metric is often used to stimulate improvement work and to manage expectations about the cycle time of specific work items in the team. The Sprint Review and Sprint Retrospective are moments to inspect Cycle Time and take action if necessary.