operation

Etymology

From Middle French operation, from Old French operacion, from Latin operātiō, from the verb operor (“I work”), from opus, operis (“work”). Equivalent to operate + -ion.

noun

1. 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.
2. The method or practice by which actions are done.
3. The act or process of operating; agency; the exertion of power, physical, mechanical, or moral.
4. A planned undertaking.
   The police ran an operation to get vagrants off the streets.
   The Katrina relief operation was considered botched.
5. A business or organization.
   We run our operation from a storefront.
   They run a multinational produce-supply operation.
6. (medicine) A surgical procedure.
   She had an operation to remove her appendix.
   This done, ſhe performs the very ſame Operation on the other Side of the Cock's Body, and there takes out the other Stone; then ſhe ſtitches up the Wounds, and lets the Fowl go about as at other Times, till the Capon is fatted in a Coup, which is commonly done from Chriſtmas to Candlemas, and after. 1750, W[illiam] Ellis, The Country Housewife's Family Companion[…], London: James Hodges; B. Collins, →OCLC, page 157
7. (computing, logic, mathematics) 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.
8. (military) A military campaign (e.g. Operation Desert Storm)
9. (obsolete) Effect produced; influence.