1 [C] (spoken 口语op) the process of cutting open a patient's body in order to deal with a part inside 手术: He had an operation to remove his appendix. 他接受手术切除阑尾。

2 [C] an organized activity that involves many people doing different things 有组织的集体行动: A rescue operation was mounted to find the missing children. 寻找失踪儿童的救援行动已经展开了。

3 [C] a business or company involving many parts 企业；公司

4 [C] an act performed by a machine, especially a computer （机器的）运作（尤指计算机的）

5 [U] the way in which you make sth work 运作、操作或工作方式: The operation of these machines is extremely simple. 这些机器的操作很简单。