operation

/ˌɑpəˈreɪʃən/
noun
  1. A planned activity or process, especially one involving many people or steps.
    • The military operation was carefully planned for months.
    • The rescue operation saved three hikers from the mountain.
    • The company launched a new marketing operation to promote the product.
  2. The state of working or being used; the act of making something function.
    • The factory will begin operation next month.
    • Please read the manual before putting the machine into operation.
    • The elevator is out of operation until the repair is complete.
  3. A medical procedure in which a doctor cuts into a patient's body to repair or remove something; surgery.
    • The operation took three hours, but it was successful.
    • She had an operation to fix her broken knee.
    • After the operation, the patient rested in the hospital for a week.
  4. A mathematical process such as addition, subtraction, multiplication, or division.
    • Addition and subtraction are basic arithmetic operations.
    • In math class, we learned a new operation called long division.
    • Each operation must be performed in the correct order.
Antonyms