n. 1
A procedure for generating a value from one or more other values (the operands).
The number of operands associated with an operation is called its arity; an operation of arity 2 is called a binary operation.
n. 2
The method by which a device performs its function.
It is dangerous to look at the beam of a laser while it is in operation.
n. 3
The method or practice by which actions are done.

Related words

Word family: opera operable operant operate operational operative operator
Phrases: black bag operation grow operation talc operation binary operation black operation dyadic operation floating point operation

Forms

Plural: operations → performances, productions, executions, activities…

Choose the right word

Operation, Action or Force?

Operation is action considered with reference to the thing acted upon, and may apply to the action of an intelligent agent or of a material substance or force; as, the operation of a medicine.

J. C. Fernald, English Synonyms and Antonyms (1914)

Example sentences

production The production has visual appeal for the audience.
activity Hey, let's make brushing our teeth a fun activity!
execution Is execution by lethal injection unconstitutional?
functioning Esperanto is undoubtedly a functioning language.
process He explained the process of putting them together.
operating Laser is currently operating! Use extreme caution!

Popularity over time

Word	1850 → 2019	Trend
operation		falling
production		falling
activity		steady
execution		steady
functioning		steady
process		rising

Use in printed books, per decade from 1850 to 2019.

By length

3 letters: act¹
4 letters: work¹, task¹
5 letters: force¹
6 letters: action², agency³, motion²
7 letters: working², process², surgery³, dynamic³
8 letters: movement², activity⁴, function², exercise³, maneuver³
9 letters: operating⁴, procedure³, execution⁴, manoeuvre
10 letters: production³, proceeding³
11 letters: performance³, functioning³
12 letters: manipulation⁵
14 letters: transformation⁴

The small number after each word is its number of syllables (action² = 2 syllables).

In other languages

Français: opération
Italiano: operazione
Español: operación
Deutsch: Operation
Català: operació