Modus operandi is a Latin phrase, approximately translated as "method of operation". In English, it is often shortened to M.O. It is someone's habits of working, particularly in the context of business or criminal investigations.The plural is modi operandi.
The term is often used in police work when discussing crime and addressing the methods employed by criminals. It is also used in criminal profiling, where it can help in finding clues to the offender's psychology. It largely consists of examining the actions used by the individuals to execute the crime, prevent its detection and facilitate escape. A suspect's modus operandi can assist in their identification, apprehension, or repression, and can also be used to determine links between crimes.