in operation
— Adjective
– English
～ being in effect or operation; "de facto apartheid is still operational even in the `new' African nations"- Leslie Marmon Silko; "bus service is in operation during the emergency"; "the company had several operating divisions"
intelligence operation
— Noun
– English
～ the operation of gathering information about an enemy
identity operator
— Noun
– English
～ an operator that leaves unchanged the element on which it operates; "the identity under numerical multiplication is 1"