Meaning of OPERATION in English
n.1 a the action or process or method of working or operating. b the state of being active or functioning (not yet in operation). c the scope or range of effectiveness of a thing's activity.
2 an active process; a discharge of a function (the operation of breathing).
3 a piece of work, esp. one in a series (often in pl.: begin operations).
4 an act of surgery performed on a patient.
5 a a strategic movement of troops, ships, etc. for military action. b preceding a code-name (Operation Overlord).
6 a financial transaction.
7 Math. the subjection of a number or quantity or function to a process affecting its value or form, e.g. multiplication, differentiation.
Phrases and idioms:
operations research operational research.
Etymology: ME f. OF f. L operatio -onis (as OPERATE)
Oxford English vocab. Оксфордский английский словарь. 2012