Agile Team Velocity is a metric used to measure the rate of progress and productivity of a project team. It is calculated by taking the total number of story points completed per sprint, divided by the total team size over the same time period. This allows teams to identify bottlenecks, allocate resources accordingly, and adjust workloads to ensure successful completion of the project. Knowing this metric can help teams keep track of their progress, hold each other accountable, and improve overall efficiency.