Final answer:
A preparatory command in military drill specifies the movement and sets the timing for the movement.
Step-by-step explanation:
In the context of military drill, a preparatory command is an oral order that specifies the movement to be performed and sets the timing for the movement. It is usually followed by the command of execution, which initiates the movement.
For example, in a drill exercise, the preparatory command might be 'Forward,' indicating that the soldiers should prepare to move forward. The command of execution would then be 'March,' which would signal them to start moving forward.
This structure of giving drill commands helps to ensure synchronized movements and maintain discipline within military formations.