[op.er.a.tion] n [ME operacioun, fr. MF operation, fr. L operation-, operatio, fr. operari] (14c) 1: performance of a practical work or of something involving the practical application of principles or processes
2. a: an exertion of power or influence "the ~ of a drug" b: the quality or state of being functional or operative "the plant is now in ~" c: a method or manner of functioning "a machine of very simple ~"
3: efficacy, potency--archaic except in legal usage
4: a procedure carried out on a living body usu. with instruments esp. for the repair of damage or the restoration of health
5: any of various mathematical or logical processes (as addition) of deriving one entity from others according to a rule
6. a: a usu. military action, mission, or maneuver including its planning and execution b pl: the office on the flight line of an airfield where pilots file clearance for flights and where flying from the field is controlled c pl: the agency of an organization charged with carrying on the principal planning and operating functions of a headquarters and its subordinate units 7: a business transaction esp. when speculative 8: a single step performed by a computer in the execution of a program