The act or process of operating; agency; the exertion of power, physical, mechanical or moral. Speculative painting without the assistance of manual operation, can never attain to perfection. The pain and sickness caused by manna are the effects of its operation on the stomach. So we speak of the operation of motives, reasons or arguments on the mind, the operation of causes.

Action; effect. Many medicinal drugs of rare operation.

Process; manipulation; series of acts in experiments; as in chimistry or metallurgy.

In surgery, any methodical action of the hand, or of the hand with instruments, on the human body, with a view to heal a part diseased, fractured or dislocated, as in amputation.

Action or movements of an army or fleet; as military or naval operations.

Movements of machinery.

Movements of any physical body.