noun effect produced; influence.
2. operation ·noun the method of working; mode of action.
3. operation ·noun the act or process of operating; agency; the exertion of power, physical, mechanical, or moral.
4. operation ·noun something to be done; some transformation to be made upon quantities, the transformation being indicated either by rules or symbols.
5. operation ·noun that which is operated or accomplished; an effect brought about in accordance with a definite plan; as, military or naval operations.
6. operation ·noun 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.