The fact or condition of functioning or being active
An active process; a discharge of a function
A business organization; a company
An activity in which such an organization is involved
An act of surgery performed on a patient
A piece of organized and concerted activity involving a number of people, esp. members of the armed forces or the police
Preceding a code name for such an activity
A process in which a number, quantity, expression, etc., is altered or manipulated according to formal rules, such as those of addition, multiplication, and differentiation