1. (

• operation

) the state of being in effect or being operative; "that rule is no longer in operation" ;

2. (

• operation ,

) a business especially one run on a large scale; "a large-scale farming operation"; "a multinational operation"; "they paid taxes on every stage of the operation"; "they had to consolidate their operations" ;

3. (

• operation ,

) a planned activity involving many people performing various actions; "they organized a rescue operation"; "the biggest police operation in French history"; "running a restaurant is quite an operation"; "consolidate the companies various operations" ;

4. (

• operation

) (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" ;

5. (

• operation ,
• military_operation

) activity by a military or naval force (as a maneuver or campaign); "it was a joint operation of the navy and air force" ;

6. (

• operation ,
• surgery ,
• surgical_operation ,
• surgical_procedure ,
• surgical_process

) 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"; "he died while undergoing surgery" ;

7. (

• operation ,
• procedure ,

) 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"; "certain machine tool operations" ;

8. (

• operation ,
• functioning ,
• performance

) process or manner of functioning or operating; "the power of its engine determines its operation"; "the plane's operation in high winds"; "they compared the cooking performance of each oven"; "the jet's performance conformed to high standards" ;

9. (

• process ,
• cognitive_process ,
• mental_process ,
• operation ,
• cognitive_operation

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

10. (

• mathematical_process ,
• mathematical_operation ,
• operation ,

) (mathematics) calculation by mathematical methods; "the problems at the end of the chapter demonstrated the mathematical processes involved in the derivation"; "they were learning the basic operations of arithmetic" ;

11. (

• operation ,

) the activity of operating something (a machine or business etc.); "her smooth operation of the vehicle gave us a surprisingly comfortable ride" ;