operation

/ˌɑp·əˈreɪ·ʃən/ n [C/U] (WORK)

Definition

› an act or process of working, doing something, being in action, or having an effect: [U] Several printing presses are in operation (= working) at the moment. [C] Setting a mousetrap is a delicate operation (= act of doing something). › An operation is also an activity planned to achieve something: [C] a rescue operation

(Definition of operation n (WORK) from the Cambridge Academic Content Dictionary © Cambridge University Press)