Scientific Operation.

Covert operation, a military or political action that is both clandestine and denied by the government undertaking the action.

Operations Support Systems used in the telecommunications industry

Military operation, a military action (usually in a military campaign) using deployed forces.

In computer science, an operation is called an instruction.

Sting operation, an operation designed to catch a person committing a crime by means of deception.

Anomalous operation, in parapsychology, a term describing a broad category of purported paranormal effects.

Operation of law, a legal term that indicates that a right or liability has been created for a part.

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 a name.

Business operations, manufacturing operations, operations management.

Musical operations such as transposition, inversion, multiplication, permutation, counterpoint.

Operation (game), a battery-operated game of physical skill.