operation

American  

[op-uh-rey-shuhn] / ˌɒp əˈreɪ ʃən /

noun

1. an act or instance, process, or manner of functioning or operating.

2. the state of being operative (usually preceded by in orinto ).

   a rule no longer in operation.

3. the power to act; efficacy, influence, or force.

4. the exertion of force, power, or influence; agency.

   the operation of alcohol on the mind.

5. a process of a practical or mechanical nature in some form of work or production.

   a delicate operation in watchmaking.

6. a course or procedure of productive or industrial activity.

   building operations.

7. a particular process or course.

   mental operations.

8. a business transaction, especially one of a speculative nature; deal.

   a shady operation.

9. a business, especially one run on a large scale.

   a multinational operation.

10. Surgery. a procedure aimed at restoring or improving the health of a patient, as by correcting a malformation, removing diseased parts, implanting new parts, etc.

11. Mathematics.

    1. a mathematical process, as addition, multiplication, or differentiation.

    2. the action of applying a mathematical process to a quantity or quantities.

12. Computers. any discrete activity or action that is performed by a computer, as reading, writing, processing, sending, or receiving data.

    The http request operation has timed out.

13. Military.

    1. a campaign, mission, maneuver, or action.

    2. Usually operations the conduct of a campaign, mission, etc.

    3. operations, a headquarters, office, or place from which a military campaign, air traffic to and from an airfield, or any of various other activities, is planned, conducted, and controlled.

    4. operations, the people who work at such a headquarters.

---

operation British  

/ ˌɒpəˈreɪʃən /

noun

1. the act, process, or manner of operating

2. the state of being in effect, in action, or operative (esp in the phrases in or into operation )

3. a process, method, or series of acts, esp of a practical or mechanical nature

4. surgery any manipulation of the body or one of its organs or parts to repair damage, arrest the progress of a disease, remove foreign matter, etc

5. 1. a military or naval action, such as a campaign, manoeuvre, etc

   2. ( capital and prenominal when part of a name )

      Operation Crossbow

6. maths

   1. any procedure, such as addition, multiplication, involution, or differentiation, in which one or more numbers or quantities are operated upon according to specific rules

   2. a function from a set onto itself

7. a commercial or financial transaction

---

operation Scientific  

/ ŏp′ə-rā′shən /

1. Medicine A surgical procedure for remedying an injury, ailment, defect, or dysfunction.

2. Mathematics A process or action, such as addition, substitution, transposition, or differentiation, performed in a specified sequence and in accordance with specific rules.

3. A logical operation.

4. Computer Science An action resulting from a single instruction.

---

Other Word Forms

• misoperation noun
• preoperation noun
• reoperation noun
• suboperation noun

Etymology

Origin of operation

First recorded in 1350–1400; Middle English operacioun, oparacion, operation, from Latin operātiōn- (stem of operātiō ), equivalent to operāt(us) + -iōn- noun suffix of action or condition; operate

Example Sentences

Unlocking the strait promises to be the next phase of the war, either through a negotiated peace agreement or a military operation.

From The Wall Street Journal • Apr. 2, 2026

Perhaps this could all be done more quickly than securing the Strait of Hormuz or occupying Kharg, but it’s not an in-and-out operation like Venezuela.

From Slate • Apr. 1, 2026

Oracle’s stake in TikTok’s U.S. operation, which includes other managing investors such as Silver Lake and MGX, is roughly $2 billion, according to a March filing from Oracle.

From Los Angeles Times • Apr. 1, 2026

Crude was still trading well above $100 a barrel, however, and market watchers said any US ground operation or wider Iranian retaliation could send prices to levels not seen for almost two decades.

From Barron's • Mar. 31, 2026

Hunt and Liddy set the operation for Labor Day weekend, when Fielding’s building should be quiet and empty.

From "Most Dangerous: Daniel Ellsberg and the Secret History of the Vietnam War" by Steve Sheinkin

Related Words

• action
• activity
• affair
• agency
• application
• deal
• effort
• enterprise
• exercise
• force
• movement
• procedure
• process
• service
• transaction
• trip
• use
• work