WordNet

process or manner of functioning or operating; "the power of its engine determines its operation"; "the planes operation in high winds"; "they compared the cooking performance of each oven"; "the jets performance conformed to high standards" (同)functioning, performance
(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"
the state of being in effect or being operative; "that rule is no longer in operation"
activity by a military or naval force (as a maneuver or campaign); "it was a joint operation of the navy and air force" (同)military operation
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" (同)procedure
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" (同)surgery, surgical_operation, surgical_procedure, surgical process
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"
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"
the activity of operating something (a machine or business etc.); "her smooth operation of the vehicle gave us a surprisingly comfortable ride"
financial transactions at a brokerage; having to do with the execution of trades and keeping customer records (同)trading operations

PrepTutorEJDIC

〈U〉(…)『作用』,働き;(機械などを)『動かすこと』,操作,(企業などの)運営《+『of』+『名』》 / 〈U〉(機械・機能などが)『動いている状態』,働いている状態,(法律など)有効である状態 / 〈C〉(人に対する…の)『手術』《+『on』〈人〉+『for』+『名』〈患部・病名〉》 / 〈C〉《複数形で》(特に,軍の)行動;《しばしばO-》…作戦 / 〈C〉運算,演算