Modus Operandi refers to the detailed methodology or the process adopted for the execution of a task. It refers to a particular pattern that is repeated exactly over and over for the completion of the task at hand.
This term is usually used in criminal cases but is not restricted to the same as it refers to any specific pattern or series of functions that are used by an individual or an organisation to meet the desired goal.
The term has Latin origins and is more commonly referred to as MO.