Definition of "Operation" :
noun: the activity of operating something (a machine or business etc.)
"Her smooth operation of the vehicle gave us a surprisingly comfortable ride."
noun: a planned activity involving many people performing various actions
"They organized a rescue operation."
noun: a process or series of acts especially of a practical or mechanical nature involved in a particular form of work
"The operations in building a house."
noun: a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body
"They will schedule the operation as soon as an operating room is available."
noun: (mathematics) calculation by mathematical methods
"They were learning the basic operations of arithmetic."
noun: activity by a military or naval force (as a maneuver or campaign)
"It was a joint operation of the navy and air force."
noun: a business especially one run on a large scale
"A large-scale farming operation."
noun: (psychology) the performance of some composite cognitive activity; an operation that affects mental contents
"The cognitive operation of remembering."
noun: (computer science) data processing in which the result is completely specified by a rule (especially the processing that results from a single instruction)
"It can perform millions of operations per second."
noun: process or manner of functioning or operating
"The power of its engine determines its operation."
noun: the state of being in effect or being operative
"That rule is no longer in operation."