command, order, direction, instruction
这些名词均含“命令”之意。
command : 较正式用词，强调权威性、全局性和强制性。
The general issued a command that all of them should come at six o'clock.
将军颁布了一道命令, 所有的人都要在六点钟到。
order : 普通用词，侧重指具体的命令。
He gave orders that the job be done in three days.
他指示三天内完成这项工作。
direction : 正式用词，指口头或书面的指示或命令。内容不一定详尽，语气较缓和，不太强调强制性。也可指指导性的说明。
He did not give any directions.
他没有作任何指示。
instruction : 书面用词，指不容违反、不容****的命令。也多指包含具体说明的指示。
They had received instructions to watch him.
他们收到了监视他的命令。