operation
operation — noun
1. a medical procedure in which a doctor cuts into the body to remove, repair, or r
a medical procedure in which a doctor cuts into the body to remove, repair, or replace a part that is damaged or unhealthy.
Lena had an operation on her knee after the skiing fall.
pattern: operation on [body part]
The child needed an emergency operation to stop the bleeding.
collocation: emergency operation
After the heart operation, Mr. Wu walked slowly at first.
Doctors moved the operation to Friday because the fever remained high.
- have an operation
- heart operation
- emergency operation
- operation on your knee
Grammar Patterns
have an operation
operation on [body part]
Usage Note
Most often follows have, need, undergo, or perform, and is often followed by 'on' plus the body part. In everyday use, patients have an operation and doctors perform one.
Common Mistakes
2. the condition of working and ready to be used, or of having legal effect at that
the condition of working and ready to be used, or of having legal effect at that time.
By six o'clock, the bakery ovens were in operation again.
fixed phrase: in operation
The new safety rule comes into operation next Monday.
fixed phrase: come into operation
Only one lift remained in operation after the power cut.
The school bus service is not in operation during summer break.
- in operation
- back in operation
- come into operation
- remain in operation
- shutdown
the state of being stopped and not working
Grammar Patterns
in operation
come into operation
Usage Note
Often follows be, remain, or come into. Common with machines, services, and rules rather than with people.
Common Mistakes
3. how a machine or system works, including the way its parts act together and the
how a machine or system works, including the way its parts act together and the way it is used correctly.
The manual explains the operation of the heating system in clear steps.
pattern: operation of [system]
A short class taught new nurses the safe operation of the pump.
collocation: safe operation
Visitors watched the windmill's operation as its wooden arms turned slowly.
Snow can affect the smooth operation of train doors.
collocation: smooth operation
- operation of a system
- safe operation
- smooth operation
- manual of operation
- functioning
focuses on the way something works, not on a person controlling it
- working
more everyday, but less precise in technical writing
- handling
focuses more narrowly on the user's control of equipment
Grammar Patterns
operation of [machine/system]
safe operation
smooth operation
Usage Note
Most often appears in 'operation of' phrases with machines, systems, and equipment. Distinguish from sense 2: this sense focuses on how something works or is handled, not simply whether it is active.
Common Mistakes
4. a carefully organized action involving several people, often by the military, po
a carefully organized action involving several people, often by the military, police, or rescue teams, to achieve a clear goal.
Coast guards began a rescue operation after the fishing boat sank.
collocation: rescue operation
Police planned a dawn operation to catch the robbery gang.
pattern: operation to + verb
The army ended the mountain operation before heavy snow arrived.
Doctors and soldiers joined the airlift operation after the quake.
- rescue operation
- military operation
- search operation
- airlift operation
Grammar Patterns
rescue operation
operation to + verb
Usage Note
Common with a noun before it showing purpose, such as rescue, search, or military. Distinguish from sense 1: both may be planned, but this sense is a wider group action rather than treatment on a body.
Common Mistakes
5. the day-to-day work of running a company or part of an industry, especially the
the day-to-day work of running a company or part of an industry, especially the practical side.
After the flood, airport operations returned to normal by evening.
often plural: operations
The company moved its European operations to Dublin last year.
business use: regional operations
Sara manages farm operations while her brother sells the crops.
Higher fuel costs forced ferry operations between Keelung and Matsu to shrink.
- airport operations
- regional operations
- farm operations
- shipping operations
- running
informal and broad; focuses on keeping something going
- management
focuses more on control and decision-making than practical work
- logistics
narrower; focuses on movement, supply, and organization
- shutdown
a stop in business or industrial activity
Grammar Patterns
operations in [region]
airport operations
Usage Note
Very often used in the plural, especially for company departments, airports, factories, and regional business work. Distinguish from sense 7: this sense is the running work itself, not the business as a single organization.
Common Mistakes
6. a rule-based calculation such as addition or division that turns one number or q
a rule-based calculation such as addition or division that turns one number or quantity into another.
Addition is the first operation children learn at school.
basic mathematical operation
The app performs the same operation on every number in Mia's table.
pattern: operation on [number]
On the board, Mr. Chen showed the division operation step by step.
To turn 48 into 12, division is the right operation.
- mathematical operation
- basic operations
- perform an operation
- operation on a number
- calculation
broader everyday word for working out numbers
- process
broader and not limited to mathematics
- function
more technical and used for special mathematical relations
Grammar Patterns
mathematical operation
operation on [number]
Usage Note
Usually used when people name, choose, or repeat a calculation rule. Distinguish from sense 3: this sense is about numbers and formulas, not the working of a machine or system.
Common Mistakes
7. a business considered as the people, work, and systems that keep it running.
a business considered as the people, work, and systems that keep it running.
The brothers turned their food truck into a larger operation.
grow a small business into an operation
What began in one garage is now a global software operation.
Aunt Mei runs a flower-growing operation outside Tainan.
pattern: run an operation
The tax office checked whether the family restaurant operation kept proper records.
- small operation
- family operation
- cash-only operation
- software operation
- business
the broad everyday word
- company
a standard neutral term, often more formal than 'operation'
- enterprise
more formal and often used for larger or ambitious businesses
Grammar Patterns
run an operation
a small operation
Usage Note
Often used for a business that feels practical, busy, or somewhat informal in tone. Distinguish from sense 5: this sense names the business itself, while sense 5 is the work of running it.
Common Mistakes
Word family
- operateverbB2
- operatornounB2
- operationaladjectiveC1
- operativeadjectiveC2
Synonym discussion
Sense: noun/1
For the medical sense, operation and surgery are close, but not identical. Operation is the everyday countable word for one event: an operation on your knee, a heart operation. Surgery can name the same kind of treatment, but it also works as a broader field or method, and in British English it can even mean a doctor's office. Procedure is wider and more neutral; it includes operations but also tests such as endoscopy. Treatment is wider still: medicine, rest, and physical therapy are all treatments, even when no cutting is involved. Intervention sounds more formal and is common in hospital writing when doctors step in to change a patient's condition. You might say Maya had an operation on Tuesday, the surgery was successful, and her treatment continues at home.
Etymology
Operation came into English from Old French operation, based on Latin operatio, from operari, meaning 'to work' or 'to carry out'. Behind that Latin verb is opus, meaning 'work'. This history helps explain why the word now covers active working, organized action, business activity, and surgical work on the body.