1. the act or process of operating or functioning.
2. the state of being operative or functional: a factory in operation.
3. A process or series of acts involved in a particular form of work: the operation of building a house.
4. an instance or method of efficient, productive activity: that restaurant is quite an operation.
5. an unethical or illegal business: a fencing operation for stolen goods.
6. medicine A surgical procedure for remedying an injury, ailment, defect, or dysfunction.
7. mathematics A process or action, such as addition, substitution, transposition, or differentiation, performed in a specified sequence and in accordance with specific rules.
8. A logical operation.
9. computer science an action resulting from a single instruction.
10. A military or naval action, campaign, or mission.
11. the headquarters or center from which a military action, flights into and out of an airfield, or other activities are controlled.
12. the division of an organization that carries out the major planning and operating functions.

1. the method by which a device performs its function.
2. the method or practice by which actions are done.
3. A planned undertaking.
4. A business or organization.
5. a surgical procedure.
6. a procedure for generating a value from one or more other values (the operands; the value for any particular operands is unique)
7. a military campaign (e.g. operation desert storm)

1. the act or process of operating; agency; the exertion of power, physical, mechanical, or moral.
2. the method of working; mode of action.
3. that which is operated or accomplished; an effect brought about in accordance with a definite plan.
4. effect produced; influence.
5. something to be done; some transformation to be made upon quantities or mathematical objects, the transformation being indicated either by rules or symbols.
6. any methodical action of the hand, or of the hand with instruments, on the human body, to produce a curative or remedial effect, as in amputation, etc.

1. action; working; agency; exertion of power or influence; specifically, in psychology, the exertion of any mental power, especially an active power.
2. A specific act or activity.
3. the course of action or series of acts by which some result is accomplished; process.
4. in mathematics, the substitution of one quantity for another, or the act of passing from one to the other, the second quantity being definitely related to the first, either in value or in form. an operation must not be confounded with the process by which the operation is effected. thus, there is but one operation of extracting the cube root of a number, but there are several different processes.
5. in war, the act of carrying out preconcerted measures by regular movements: as, military or naval operations.
6. the state of being at work; active exercise of some specific function or office; systematic action: as, the machine is in operation.
7. method of working; action.
8. power exercised in producing an effect; peculiar efficacy of action; characteristic property or virtue.
9. impulse; tendency to act.
10. an operation for Dupuytren's contraction, consisting in the subcutaneous division of the contracted bands of the palmar fascia.
11. for vaginal atresia: a method of dilatation by the use of the finger and dull instruments, rather than by cutting.
12. the extraction of a nasal polypus by the aid of an incision made in the middle line of the soft palate.
13. A medio-lateral operation of lithotomy, with an angular staff.
14. see Dieffenbach's rhinoplastic operation and indian rhinoplastic operation.
15. for procidentia uteri: a denudation on the anterior and posterior walls of the vagina, and formation of longitudinal septum.
16. A pure tarsometatarsal disarticulation. see hey's operation.
17. Subastragaloid operation.
18. for hernia: an operation without opening the sac.
19. an operation for staphylorrhaphy, in which liberating incisions are made on each side of the suture.
20.
21. embryotomy by decapitation.
22. amputation by a circular incision down to the bone.
23. removal of epithelioma of the lip by a V-shaped incision.
24. an operation for the radical cure of hernia by closing the internal ring by a pad formed of the hernial sac.
25. excision of a wedge-shaped piece from the tarsus in order to restore the arch in fiat-foot.
26. an operation for theclosure of harelip.
27. removal of the necrosed portion of a bone, allowing the cavity to fill with blood which clots and later becomes organized.

1. activity by a military or naval force (as a maneuver or campaign)
2. a planned activity involving many people performing various actions
3. (psychology) the performance of some composite cognitive activity; an operation that affects mental contents
4. the activity of operating something (a machine or business etc.)
5. a business especially one run on a large scale
6. (mathematics) calculation by mathematical methods
7. the state of being in effect or being operative
8. process or manner of functioning or operating
9. a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body
10. a process or series of acts especially of a practical or mechanical nature involved in a particular form of work
11. (computer science) data processing in which the result is completely specified by a rule (especially the processing that results from a single instruction)