operation - noun

the state of being in effect or being operative

a business especially one run on a large scale

a planned activity involving many people performing various actions

(computer science) data processing in which the result is completely specified by a rule (especially the processing that results from a single instruction)

activity by a military or naval force (as a maneuver or campaign)

a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body

a process or series of acts especially of a practical or mechanical nature involved in a particular form of work

process or manner of functioning or operating

(psychology) the performance of some composite cognitive activity; an operation that affects mental contents

(mathematics) calculation by mathematical methods

the activity of operating something (a machine or business etc.)

operation - thesaurus

functioning   performance   procedure   process   surgery