/ ˌɒpəˈreɪʃn; NAmE ˌɑːp-/ noun
(also BrE informal op ) [ C ] operation (on sb) (for sth) | operation (to do sth) the process of cutting open a part of a person's body in order to remove or repair a damaged part :
an operation on her lung to remove a tumour
Will I need to have an operation ?
He underwent a three-hour heart operation.
Doctors performed an emergency operation for appendicitis last night.
[ C ] an organized activity that involves several people doing different things :
a security operation
The police have launched a major operation against drug suppliers.
the UN peacekeeping operations
[ C ] a business or company involving many parts :
a huge multinational operation
[ C ] the activity or work done in an area of business or industry :
the firm's banking operations overseas
[ C , U ] an act performed by a machine, especially a computer :
The whole operation is performed in less than three seconds.
MACHINE / SYSTEM
[ U ] the way that parts of a machine or a system work; the process of making sth work :
Regular servicing guarantees the smooth operation of the engine.
Operation of the device is extremely simple.
[ C , usually pl. ] military activity :
He was the officer in charge of operations.
[ C ] a process in which a number or quantity is changed by adding, multiplying, etc.
- in operation
- come into operation
- put sth into operation
late Middle English : via Old French from Latin operatio(n-) , from the verb operari expend labour on, from opus , oper- work.