What does 'Push Back' refer to in aviation?

'Push Back' in aviation specifically refers to the process of using a tug to move the aircraft away from the terminal gate. This is an essential step that occurs after passengers have boarded and prior to the aircraft beginning its taxi to the runway for takeoff. The tug connects to the aircraft's nose gear, assisting in maneuvering it backward in a controlled manner, which is crucial due to the limited visibility for pilots at this stage.

This process is critical because it ensures safety and efficiency on the ground. Once the aircraft is sufficiently clear of the gate and adjacent terminal facilities, the pilots can take over and begin the taxi process towards the runway. The other options do not accurately describe 'Push Back,' as they pertain to different operational procedures in aviation.