v. t. 1. To produce, as an effect; to cause. [ 1913 Webster ]

The same cause would operate a diminution of the value of stock. A. Hamilton. [ 1913 Webster ]

2. To put into, or to continue in, operation or activity; to work; as, to operate a machine. [ 1913 Webster ]

v. i. [ imp. & p. p. Operated p. pr. & vb. n. Operating. ] [ L. operatus, p. p. of operari to work, fr. opus, operis, work, labor; akin to Skr. apas, and also to G. üben to exercise, OHG. uoben, Icel. æfa. Cf. Inure, Maneuver, Ure. ] 1. To perform a work or labor; to exert power or strength, physical or mechanical; to act. [ 1913 Webster ]

2. To produce an appropriate physical effect; to issue in the result designed by nature; especially (Med.), to take appropriate effect on the human system. [ 1913 Webster ]

3. To act or produce effect on the mind; to exert moral power or influence. [ 1913 Webster ]

The virtues of private persons operate but on a few. Atterbury. [ 1913 Webster ]

A plain, convincing reason operates on the mind both of a learned and ignorant hearer as long as they live. Swift. [ 1913 Webster ]

4. (Surg.) To perform some manual act upon a human body in a methodical manner, and usually with instruments, with a view to restore soundness or health, as in amputation, lithotomy, etc. [ 1913 Webster ]

5. To deal in stocks or any commodity with a view to speculative profits. [ Brokers' Cant ] [ 1913 Webster ]

{ } a. Of or pertaining to the opera or to operas; characteristic of, suitable for, or resembling, the opera; as, an operatic voice. [ 1913 Webster +PJC ]

adj. 1. pr. p. of operate; as, the operating conditions of the oxidation pond. [ WordNet 1.5 ]

2. having an effect or influence.
Syn. -- at work(predicate), in operation, operant. [ WordNet 1.5 ]

n. [ L. operatio: cf. F. opération. ] 1. The act or process of operating; agency; the exertion of power, physical, mechanical, or moral. [ 1913 Webster ]

The pain and sickness caused by manna are the effects of its operation on the stomach. Locke. [ 1913 Webster ]

Speculative painting, without the assistance of manual operation, can never attain to perfection. Dryden. [ 1913 Webster ]

2. The method of working; mode of action. [ 1913 Webster ]

3. That which is operated or accomplished; an effect brought about in accordance with a definite plan; as, military or naval operations. [ 1913 Webster ]

4. Effect produced; influence. [ Obs. ] [ 1913 Webster ]

The bards . . . had great operation on the vulgar. Fuller. [ 1913 Webster ]

5. (Math.) Something to be done; some transformation to be made upon quantities or mathematical objects, the transformation being indicated either by rules or symbols. [ 1913 Webster ]

6. (Surg.) 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. [ 1913 Webster ]

Calculus of operations. See under Calculus. [ 1913 Webster ]

adj. 1. of or pertaining to operations; as, operational procedure. [ WordNet 1.5 ]

2. Fit or ready for service; available and in working condition; as, an operational aircraft. Opposite of out-of-service.
Syn. -- functional, usable, useable, in order(predicate), in working order(predicate), operable. [ WordNet 1.5 ]

3. (Mil.) of or intended for or involved in military operations. Opposite of nonoperational. [ WordNet 1.5 ]

4. In force; not expired or annulled; -- of rules or laws. [ WordNet 1.5 ]

de facto apartheid still operational even in the `new' African nations Leslie Marmon Silko [ WordNet 1.5 ]

n. (Philos.) the doctrine that the meaning of a proposition consists of the operations involved in defining, proving, or applying it. [ WordNet 1.5 ]

adj. (Philos.) Of or pertaining to operationalism. operationalist doctrine [ WordNet 1.5 ]

n. (Finance) financial transactions at a brokerage; having to do with the execution of trades and keeping customer records.
Syn. -- trading operations. [ WordNet 1.5 ]

n. 1. A skilled worker; an artisan; esp., one who operates a machine in a mill or manufactory. [ 1913 Webster ]

2. One who acts as an agent of another, especially a detective or spy. [ PJC ]