operation

Medical treatment in which a doctor cuts into the body to repair or remove something.

• My father needs an operation.
• The operation on her knee went well.
• How long will you stay in hospital after the operation?

How to use it: an operation on something (He had an operation on his knee.); an operation to do something (She needs an operation to remove the lump.)

Similar words: surgery, surgical procedure

Common phrases: have an operation, heart operation, operation on something, emergency operation

A planned activity by a group working towards a goal, especially soldiers, police, or rescue workers.

• The rescue operation saved six people.
• Soldiers carried out the operation at night.
• Police launched an operation to find the stolen cars.

Similar words: mission, campaign

Common phrases: military operation, rescue operation, police operation, launch an operation

A business or part of a business, including the work it does.

• Their bakery is a small operation.
• The company expanded its overseas operations.
• She manages the firm's entire European operation.

Similar words: business, enterprise

Common phrases: business operation, overseas operation, expand an operation, small operation

The way a machine works, or the state of working.

• The lift is back in operation.
• This button controls the operation of the fan.
• Read the instructions for safe operation before using the machine.

How to use it: in operation (Keep your hands away while the machine is in operation.); the operation of something (The guide explains the operation of the pump.)

Similar words: functioning, working

Common phrases: in operation, safe operation, automatic operation, operation of something

An action with numbers, such as adding or dividing, shown by a mathematical sign.

• Addition is a basic mathematical operation.
• Which operation does this symbol represent?
• Perform the operations inside the brackets first.

Similar words: calculation

Common phrases: mathematical operation, basic operation, operation symbol, arithmetic operation

The way an activity, process, or system is carried out.

• Their method of operation was simple.
• The review examined the operation of the complaints system.
• Clear rules are essential for the smooth operation of the scheme.

How to use it: the operation of something (We reviewed the operation of the new rules.)

Similar words: working, functioning, procedure

Common phrases: method of operation, mode of operation, normal operation, operation of something