Operation

The word operation can mean any of several things:

The method, act, process, or effect of using a device or system. See military operations, manufacturing operations, anomalous operation.
In mathematics, a well-defined action that, when applied to any permissible combination of known entities, produces a new entity, e.g. , the process of addition in arithmetic--in adding 5 and 3 to obtain 8, the numbers 5 and 3 are the operands, the number 8 is the result, and the plus sign is the operator indicating that the operation performed is addition. See operator, unary operation, binary operation.
In computer programming, a program step, usually specified by a part of an instruction word, that is undertaken or executed by a computer. Gates such as And, Or and Not are also operations.

Note: Examples of operations include addition, multiplication, extraction, comparison, bit-shift, transfer.