operation

noun

1 MEDICAL (C) the process of cutting into someone's body to repair or remove a part that is damaged: a heart bypass operation | She had a bad operation, she had a hysterectomy.

(+ on/for): She's going to have an operation on her knee. | perform an operation: an operation only the most skilled surgeon could perform

2 SET OF ACTIONS (C) a set of planned actions or activities for a particular purpose: The whole operation should only take about ten minutes to perform. | a search and rescue operation, expertly performed

3 MACHINE/SYSTEM (U)

a) the way the parts of a machine or system work together: to maintain proper engine operation (=working) | in operation (=working): Protective clothing must be worn when the machine is in operation.

b) the process of making a machine or system work: Operation of the system is automatic.

4 BUSINESS

a) (C) a business, company, or organization, especially one with many parts: Their huge interstate operation reportedly brings in $20 million a year.

b) (C, U) the work or activities done by a business, organization etc, or the process of doing this work: Many small businesses fail in the first year of operation. | be in operation: Chris's courier service has only been in operation for two months.

5 PRINCIPLE/LAW/PLAN ETC (U) the way something such as a principle, law etc works or has an effect: the operation of the laws of gravity | in operation: a clear example of Murphy's law in operation | come/go into operation (=begin to have an effect): The Act will come into operation later this year. | put/bring sth into operation (=make something start to work)

6 MILITARY/POLICE ACTION (C) a planned military or police action, especially one that involves a lot of people: an espionage operation

7 COMPUTERS (C) technical an action done by a computer: a multi-tasking machine performing millions of operations per second