Modus operandi (often used in the abbreviated forms M.O. or simply Method) is a Latin phrase, approximately translated as "method of operating" The term is used in English to describe someone's habits or manner of working, the method of operating or functioning. It is often used in a criminal sense, to profile the methods employed by individuals during the execution of a crime, and may also be used in offender profiling,2 where it can also be used to find clues to the perpetrator's psychology.3 It largely consists of the methods used to execute the crime, prevent detection, and facilitate escape.

One who has a mania for music.

stands for modus operandi which translates as method of operation

slang that means a lot or in an excessive amount.

short for "modus operandi"...a person's way of doing things or their style.

Short for homo. Mainly used by the gay community when referring to each other. Rarely used as a homophobic insult.

Not an urban term at all, but a legal one. Short for Modus Operandi (method of operation). One's either habitual or premeditated way of doing things.