What does "T-1" refer to in deployment timing?

The term "T-1" in deployment timing specifically indicates "one day before deployment." This terminology is used in various operational contexts, particularly in military and logistical planning, to signify a countdown to a specific operation or event. "T" represents the time of deployment, and the number following the "T" denotes how many time units are remaining before that event occurs. Thus, "T-1" effectively communicates that there is one day left to finalize preparations, conduct necessary briefings, and ensure that all personnel and resources are ready to proceed with the deployment. Understanding this notation is crucial for effective planning and coordination in deployment scenarios.