/kəˈmɑ:nd; US -ˈmænd ||; kəˈmænd/noun1 [C] an order 命令: The captain's commands must be obeyed without question. 必须服从船长的指挥，不得有异议。
2 [C] (computing计算机技术) an instruction given to a computer （给计算机下的）指令
3 [U] control over sb/sth 控制: Who is in command of the expedition? 谁指挥这次远征？to take command ofa situation 控制局势
4 [sing] the state of being able to do or use sth well 掌握: She has a good command of French. 她精通法语。
at/by sb's command(
formal 正式) because you were ordered by sb 奉行命令:
At the command of their officer the troops opened fire. 军官一声命下，士兵立即开火。 be at sb's command to be ready to obey sb 随时待命:
I'm completely at your command. 我一切听从您的指示。