order (something that someone in authority tells you that you must do): I take orders only from my manager.
command (an official order): The captain issued the command to retreat.
instruction (an order or direction): I’m under instructions not to let anyone in.
directive formal (an official instruction): I have received a directive from headquarters on working hours.
decree formal (an order from a ruler that has the force of law): The parliament was dissolved by presidential decree.
edict formal (a decree issued by a person with power or by a government): The king issued an edict banning political demonstrations.
injunction (a court order which demands that something must or must not be done): The court has issued an injunction against the sale of this drug.