modus operandi (moh-d<<schwa>>s op-<<schwa>>-ran-dIor -dee). [Latin “a manner of operating”] A method of operating or a manner of procedure; esp. a pattern of criminal behavior so distinctive that investigators attribute it to the work of the same person <staging a fight at the train station was part of the pickpocket’s modus operandi>. — Abbr. M.O. Pl. modi operandi.
[Blacks Law 8th]