Surgery operation
An operation or operator in mathematics (see unary operation, binary operation, arity)
In language, an operation is a word which represents a function (or instruction), rather than a term or name
In computer science, an operation is called an instruction
Military operation, a military action (usually in a military campaign) using deployed forces
Covert operation, a military or political action that is both clandestine and denied by the government undertaking the action
Sting operation, an operation designed to catch a person committing a crime, by means of deception
Business operations, manufacturing operations, operations management
Operations Support Systems used in the telecommunications industry
Operation of law, a legal term that indicates that a right or liability has been created for a part
Anomalous operation, in parapsychology, a term describing a broad category of purported paranormal effects
Musical operations such as transposition, inversion, multiplication, permutation, counterpoint
Operation (game), a battery-operated game of physical skill.
Source:http://en.wikipedia.org/wiki/Operations